Gareth McKinley

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ORAL HISTORIES

Credit: Royal Society of London

Interviewed by
David Zierler
Location
Video conference
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Interview of Gareth McKinley by David Zierler on March 31, 2020,Niels Bohr Library & Archives, American Institute of Physics,College Park, MD USA,www.aip.org/history-programs/niels-bohr-library/oral-histories/44809

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Abstract

In this interview, David Zierler, Oral Historian for AIP, interviews Gareth McKinley, School of Engineering Professor of Teaching Innovation at MIT. McKinley recounts his childhood in England and his early interests in math and science. He describes his decision to study at Cambridge, where he pursued an undergraduate degree in chemical engineering, and where he participated in the Cambridge Air Squadron flying Bulldog planes. McKinley discusses his reasons for staying on at Cambridge for his MA, and his considerations about entering industry. He describes the events leading to his PhD work at MIT, and he reflects on the cultural differences he experienced in the “other Cambridge.” McKinley describes the research he was doing under the support of Reagan’s SDI program, and his dissertation work studying the nonlinear dynamics of viscoelastic flow in complex geometries. He recounts his decision to turn down an offer from DuPont and to join the faculty at Harvard. McKinley discusses his early exposure to rheology and his work at the Isaac Newton Institute, and he discusses his switch to MIT. He explains his research in the microfluids lab, his tenure as director of the Program in Polymer Science and Technology, and his work developing patents for research projects which had commercial viability. In the last portion of the interview, McKinley explains the advantages and pleasures of pursuing his research within a multidisciplinary framework, and he describes the history and contemporary development in the field of rheology.

Transcript

Zierler:

Okay. It is March 31, 2020. This is David Zierler, oral historian for the American Institute of Physics. It’s my great pleasure to be here remotely with Dr. Gareth McKinley of MIT. Dr. McKinley, thank you so much for spending time with me today.

McKinley:

You're very welcome. Looking forward to it.

Zierler:

Can you tell us your title and your affiliation at MIT?

McKinley:

Yes. So I’m in the Mechanical Engineering Department, and I’m head of something called the Hatsopoulos Microfluids lab. My actual title at the moment is the School of Engineering Professor of Teaching Innovation.

Zierler:

Okay, great. So let’s start all the way back at the beginning. Tell us about your family and your early childhood in the UK.

McKinley:

Yeah. So it’s a somewhat complicated story. I was born actually to my mother, Rosemary Jill Matthews as she was at the time, and my biological father was someone called Keri Priddle. But they ended up divorcing when I was very young, actually, and separating, and so I lived with my mother for very early years. Then when she remarried when I was two, my new father adopted me, so I changed my name from Gareth Priddle to Gareth McKinley. Middle name is Huw, and it’s one of those names that always causes some consternation with people because it’s the Welsh spelling. Gareth is a very Welsh name, and Huw is spelled H-u-w for me, which is a Welsh spelling of that name. So although my roots are in Wales originally, I grew up in the London area with my mother and an adoptive father.

Zierler:

Did you keep a relationship with your biological father?

McKinley:

I didn't at the time, unfortunately. I, in many ways, wish I had. The terms of the separation were that they weren't in touch for a long while, and actually I didn't know very much about him at all until unfortunately he passed away very early from a heart attack. He was a teacher at a school in London. Then I found out that I had four half-siblings, in fact, from a second marriage for him.

Zierler:

You only found that out at the time.

McKinley:

And I found that out at the time, yes.

Zierler:

Huh. And your adoptive father, what did he do for a living?

McKinley:

My adoptive father worked in London. He was an accountant and worked in finances for a number of companies, including a big international school travel agency, which gave me part of my love of travel.

Zierler:

Mm-hmm [yes]. And your mom, did she work outside the house?

McKinley:

She did. She was one of the… She was part of a generation of teachers, so my biological, my maternal grandfather, was a high school headmaster in London of a big London high school in north London in an area called Hackney. So some of my earliest memories are of going to school meetings with him and sitting there as he ran school meetings. Then my mother became a teacher in what we would call junior, or JMI, school—primary schools in the American terminology—and eventually became actually a headmistress of a primary school just north of London. So growing up, I remember a lot of school meetings with both my grandfather and my mother, and then of course there’s me and now my daughter just completed her master’s degree in education as well.

Zierler:

It’s a family business, it sounds like!

McKinley:

It’s a family business. It does seem to run in the family on that side, yeah.

Zierler:

Now you grew up in London proper or outside?

McKinley:

Very early years were in London proper in a northern London suburb, an area called Enfield, so north London. But when I was about five or so, we moved out to a town called Ware, which is kind of commuter belt. It’s an area just north of London in Hertfordshire. So my school years were spent in a number of little villages around there, so very nice area. Around London there’s something called the Green Belt, which was an area that they prevented building to prevent urban sprawl, and then beyond the Green Belt, there were a number of new cities, as they called them, or garden cities. Welwyn Garden City and Stevenage were the nearest towns for me growing up.

Zierler:

Now your primary school, was it public school or a private school?

McKinley:

Yeah. So primary school was very much just the little local town primary school, and then at age 11, in England you went to what we would call secondary school or grammar school. Those, back in the 1970s, used to have entrance exams. It was called the 11-plus exam in England. Then in the 1970s there was a change in government and it became very much a Labour, quite a left-wing Labour kind of socialist set of governments. They abolished those because those were viewed somewhat as elitist, and so all schools were forced to take a broad spectrum of people coming in. My year was in fact the second… I think it was the second year in which they had to have broad admission with no entrance exams. So our school size almost doubled that year. I went to high school in September 1975, and it used to be 90 students in what was called Hertford Grammar School, but it became known as Richard Hale School. We were…I can't remember what the term was now, but basically a broad acceptance, a broad admission. You spent seven years in a high school in England, unlike here where you only spend four years, and so the first few years, very much from age 11 to age 14, there’s a streaming starts to happen and you start to get selected based on performance in various subjects.

Zierler:

Did you demonstrate an early aptitude in math and science at this point?

McKinley:

I guess so. I guess you would say yes. Yes. So I, within a year or two, was streamed towards focusing more on math and physics and chemistry. In England, you used to take exams called O-levels at age 16, and then we were streamed towards those. So I took 11 O-levels in which most of them were math, physics, chemistry, biology, advanced math, but then also subjects like geography, history, and two languages, French and German.

Zierler:

Were there any particular teachers in high school that were influential in your development?

McKinley:

Yeah. You know, there are many that stick out. I’ll mention maybe four of them as ones that really stuck out. Two of them were my maths teachers—maths, as we say it in England. Both of them, I think, even though I didn't realize it at the time, were kind of instrumental in steering me towards that kind of thing. It’s the kind of thing you're not really aware of when they’re doing it. I enjoyed math classes, but one of them certainly—Paul Smith, his name was—gave me some of his old college books. He said he was getting rid of them and he gave them to me, but I think he was really just trying to awaken an interest in those things. So that was very nice. Then Robin Coxon, he was also a math teacher, also very, very influential. But then my chemistry teacher, a guy called Fred Bagguley, who was already quite senior, probably close to retirement when I was there, was just a great teacher. Kind of in the old school of “It’s my way or the highway,” and didn't necessarily adapt well to the more comprehensive style of ’70s English education, but was fantastic in terms of awakening an interest in chemistry for me as well.

Zierler:

Mm-hmm [yes], mm-hmm [yes]. Now in the English system, when you're thinking about college and opportunities for your future, are you settling on a field of study right at the beginning, or is there a general education component and then you declare a major later on?

McKinley:

Yeah. That’s a great question. There is definitely a breadth, sort of very broad in high school until age 16, and then in the English system, many people will leave school at 16 with O-levels. There’s a down-selection to only probably about two-thirds of our class stayed on for two more years to do A levels. For me, that was chemistry, physics, math, and advanced math, so you can already see a selection there.

Zierler:

Yeah.

McKinley:

Then as you start applying to colleges based on the results of your A levels, you do apply directly typically to a field. So you choose a college or university and the field, and so I was mainly applying for chemical engineering programs at Nottingham and Imperial. But there’s always the Oxbridge system in England, and that’s kind of the elite or the crème de la crème that you daren’t hope that you might get into, but you try anyway.

So there I applied to Cambridge based on, indeed, one of my teachers, Mr. Brush, who had… He was actually my French teacher, but he had a strong connection with Cambridge. On the negative side, the old boy network is very much part of it in the UK, or used to be part of it in the UK. So if your school had a strong connection with a particular college or a professor who went there, then they would steer you towards that. So my best friend in high school, he was steered towards Keble College, Oxford. He was a very good chemist and he was steered there by Fred Bagguley, our chemistry teacher, and I was steered more towards Cambridge, mainly because of my interest in chemistry and math and chemical engineering.

Zierler:

Now that seems like a pretty early age for you to settle on such a specific field of study, chemical engineering. How had you come to that topic?

McKinley:

I forget my physics teacher’s name now, but one thing I do remember him telling me at a reasonably early age. He said I was never going to be a good physicist, so I [unintelligible] school.

Zierler:

Why? What were you lacking? What were you lacking to be a good physicist?

McKinley:

That’s a very good question. I don't really know what it was because I actually liked physics a lot, but I clearly wasn’t as good at it as I was at chemistry and math. So I was steered away from physics, and chemical engineering was something that looked like… It had a mixture of chemistry and some math in it, so it looked good to me. But in Cambridge, the way the Cambridge system works, chemical engineering was kind of one of the newer subjects and so you couldn't take it straightaway. So in fact, when I matriculated at Cambridge, I matriculated in what’s called the natural sciences, the Nat. Sci. Tripos. The Tripos was a three-part program where there’s first year, second year, and third year, but the first two years were natural sciences, very much in the same style as the old natural philosophy. So it was a mixture of math, chemistry, physics. Then you had to do one last subject which was either history and philosophy of science or cell biology or crystallography, and I took cell biology. So those were my four subjects in the first year, and then by the second year you started to down-select. I actually wanted to do nothing but chemistry at that point, so I took advanced chemistry. But you couldn't do just chemistry; you had to do something else, and so I took a class called fluid mechanics because it looked like it had a combination of math and some chemistry. It was a good entrance towards chemical engineering, and that was it for me. I was hooked. So that was about my second year in Cambridge at age 20, and it was clear that fluid mechanics was going to play a big role for me after that.

Zierler:

Are there specific classes on rheology, or is that more of a generalized umbrella term for all of the various subcomponents?

McKinley:

Yeah. There was not a special subject in rheology. In fact, I think there still probably isn't at Cambridge. But my Director of Studies at Cambridge, who was a wonderful guy called Malcolm Mackley, was the Director of Studies for chemical engineering in my college. The Cambridge system is a decentralized system, so it has 26 colleges. I went to a college called Downing College, and he was the Director of Studies for the chemical engineers. There were only five of us doing chemical engineering there, and he happened to be an expert in rheology. He had done his PhD thesis at University of Bristol in that area. I’m actually planning to do an oral history with him at some point. Maybe we’ll do it remotely, given the era that we’re in. So he was partly responsible for me getting interested in it, and he was able to do a short module. There were probably about 10 or 15 lectures in our third year at Cambridge, and that was enough to really pique my interest. Then in the Cambridge system, you had to stay on for a fourth year to do what was in those days called a CPGS, which stood for a Certificate of Post-Graduate Study. It’s now become an M.Eng, but that M.Eng for me was when I really started to get interested in rheology. He suggested to me to go down into the lab and work with one of his graduate students on a project that was on molten polypropylene, which was very much where my interest in rheology started.

Zierler:

Now before we get too far afield, I’d love for you to talk about the London International Youth Science Fortnight in 1981. What was your involvement with that?

McKinley:

With that? Yeah, so that was the end of my year 11 in the English system, or Lower Sixth form as we called it, so one year before you graduated and went off to college. It was a two-week residential program in the University of London halls of residence. I happened to know about it because my maternal grandfather had been involved in helping it start through an exchange program with the US called People to People International. People to People still goes on, and People to People would send American students to the London International Youth Science Forum. They originally called it the Science Fortnight, and then many people outside the UK, of course, don't really know what a fortnight is. So they eventually found that they could call it the Science Forum and keep the acronym the same. But when I went, it was still very much the Science Fortnight.

So I was aware of it and I applied for it and was able to get a small grant of support from our local county council and went off to London. So this was the last week of July and the first week of August in the summer of 1981, and so I spent two weeks there with about 300 people together from around the world from about 50 countries. It was people who basically had won science fairs or something equivalent to that in each of their home countries. You’d all live together in two or three of the halls of residence there and attend lectures that were held at something called the IEE, the Institute for Electrical Engineers, one of these grand old institutes right on the Strand in the middle of London. So it was just a very formative time where immersed with a bunch of other people who had the same passions and same interests, most of whom were either 17 or 18. Also, you know, in the middle of London with a great town to explore, it was a really formative time for me.

I loved it so much that you attend once, but then they usually pick people who were participants to go back and serve as hosts or kind of organizers the next year. So I went back the summer of ’82 as an organizer, and then for the next four or five years I kept going back, rising up through the echelons from first just an organizer to then what was called the host of a particular hall of residents. Each of the halls of residence would have kind of a friendly competition with the other ones that the intramural sports and various science contests, and then eventually became Director of Staff and director of all the students and then eventually served on the advisory board. So it’s something I’ve kept going back to over the years, and in fact, I’m still in touch with the current organizer of it as well.

Zierler:

The other extracurricular activity I wanted to ask you about was your involvement with the Cambridge University Air Squadron when you were flying Bulldog planes in 1983 and 1984. How did you get involved with that outfit?

McKinley:

Yeah. So the first week that you go to Cambridge is only the freshmen, the incoming freshmen, are there. So it’s called Freshers’ Week, and the equivalent of the kind of week that you have here where people go ‘shopping’ to try and explore different opportunities, different clubs. It’s a bit like rush for fraternities. So during Freshers’ Week, you know, the tennis club, the rowing club, everything like that, is advertising. I was never a very good sportsman in any field. The hand-eye coordination doesn't run strong in the McKinley family, so it was clear I wasn’t going to do that. But then I liked planes, I liked fluid mechanics, and I happened to walk past this booth for the University Air Squadron. It’s a little bit like ROTC here, but because in the English system you don't… Well, in those days you didn't have to pay anything for university. It was essentially covered by the state. There was no requirement to serve in the military for six years or something like that after ROTC.

So over here in America, people typically sign up and then have to do so many years of service, but there it was really an outreach activity because they wanted connections with university students. So the RAF had a number of university air squadrons at a number of the universities. CUAS, as it was called, or the Cambridge University Air Squadron, was one of the oldest, and so I signed up to learn more about it. I went along and I think there were a couple of interviews, general questions to ensure that you were interested, that you really had a passion, and that you were interested in getting committed. So I was and essentially they taught you to fly for free. So I ended up spending four years cycling out to the airfield on the edge of Cambridge every Wednesday afternoon. Instead of going into a lab or doing an undergraduate research, we would spend time flying.

Zierler:

Were you a good pilot?

McKinley:

I was an okay pilot. I would say I learned by doing. It wasn’t one of these things where I got in the plane and people would say, “Oh, it came naturally to him.” So it was something that I learned. I knew the theory behind it, but it took some time to become a master of it. But they taught you in very much a different way than the way you would learn for a private pilot’s license over here. So we spent a lot of time doing aerobatics, so I learned to do barrel rolls and stalls and spins and spin recovery, and essentially much more of an organized or military style of flying. So it didn't come easily to me, but eventually I really took to it. Certainly when I came over here, as soon as I had some disposable income of my own, I ended up getting a private pilot’s license as well in Massachusetts.

Zierler:

Oh! Have you kept it up?

McKinley:

I kept it up until our second child was born. It was one of those ones it was an expensive and time-consuming hobby, and children have a habit of making that harder and harder to do. But I did get licensed over here and I used to fly. So you could pick up a plane on a Saturday afternoon and fly down to Cape Cod from the Boston area with the kids. We had two car seats in the back of the plane, in the little Cessna in the back, and my wife in the front. We’d fly down to Cape Cod or up to Maine for the day. So it was a great way…a great hobby, but it was not a cheap hobby and also very time-consuming. So for every hour in the air, there’s kind of flight planning, pre-flight inspection, weather planning. I only ever had visual flight rules. I never had an instrument rating, so I could only fly during the day. But you didn't become very popular if you said to your wife, “Well, you play with the kids for three hours. I’m going to go take off and go fly.”

Zierler:

[Chuckles] Yeah, right! Now the air university squadron program, was there a natural momentum that this would have led to military service if you had gone in that direction? Did you ever think about joining the RAF?

McKinley:

I thought about it very briefly. There was very much a natural connection to Officer Flight Training School. So several of the people who were in my… I’m trying to remember. There were probably 10 or 15 of us in each year, about that, and usually a couple of people dropped out, so maybe it was down to 10 by the time it was in our third year. Then several of them did actually go on to the RAF, went off to Officer Training School and then became pilots for what in those days was called a Tornado, a swing wing jet aircraft, so the British Tornado. So they ended up actually then going off, and at least one of the people that I knew there went off and served in the Falklands War1. So he became a pilot. But I would say for most people, because there was no commitment, I would say that out of the ten, probably eight of us didn't go on, or seven or eight of us didn't go on. I’ve lost track with everyone from those days now. There was no pressure to do it, but there was certainly an awareness and to make people aware of it and for the right people, there was an invitation to go further.

Zierler:

Mm-hmm [yes]. So back to the questions about your education, your formal education. So between your degrees in chemical engineering and your interest in fluid dynamics and rheology, what was your formal education in physics? Did you take any classes specifically in physics, or are you teaching yourself? Are you in the lab? Are you relying on what you learned in high school? How does this work as an undergraduate at Cambridge?

McKinley:

Yeah. As an undergraduate, it was a required class. It’s a first-year natural sciences, so one quarter of our time was doing physics. So physics in Cambridge is certainly a very rich subject that has a very rich history. The original site was a place called the Cavendish Laboratory. That had been closed down in the 1970s, and it moved out to the west of town to what was now called the New Cavendish, just an indication of how my age is as I was back in Cambridge in, what is it, September of 2019 and they’re now demolishing what was called the new Cavendish and building a new, new Cavendish right next to it. But physics had moved out of town because it was right in the middle of Cambridge, which is a very small town and buildings that had been built around Victorian Era. That’s where Rutherford and people had their labs. That’s where Rutherford had worked on atomic physics and things like that.

So now it was on the edge of town, so we’d cycle out there. There would be labs in the afternoon, kind of basic, first-year labs on experiments in physics, lectures in the morning. That was a very hard subject for me. I enjoyed it, but it was certainly much more mathematical than the kind of physics that I had been used to in school. The school curriculum had been revised and it was something called Nuffield physics2, which was kind of a new educational style of delivering physics which I’d enjoyed in school, but it didn't prepare me very well for the classical physics, quite mathematical physics that Cambridge was focused on. So I definitely struggled in the first year, and at the end of my first year, the way the English system works is the top 10% get Firsts. The middle 80% get Seconds, second-class degrees or second-class rankings, and that’s roughly split into half getting Upper Seconds and the second half getting Lower Seconds, and then a very small fraction of people get third-class passes. I finished down in the lower second category, so probably in the bottom 50% of the class. It was definitely a struggle for me.

But my tutor in those days, or Director of Studies, was a guy called Peter Duffett-Smith at Downing, who was a very, very patient man and really spent a lot of time with me. I finally got the ideas behind a lot of these things, but it didn't come naturally. But I realized like anything, if you work at it, I started to get the idea and I started to like it a lot more and would have done more physics, but clearly I hadn't done very well in the first year. I’d done much better in my chemistry, and so I started to drift more towards chemistry plus fluid mechanics, which is kind of an interesting mix, but that’s where chemical engineering was going to play a role in my third and fourth years.

Zierler:

Now as you get into your third and fourth years with your increasing focus on chemical engineering, who are the professors that you're developing close relationships with and who are serving as a mentor to you?

McKinley:

Yeah. Probably the main one is the person I mentioned already, Malcolm Mackley, who was not a Cambridge man, and very much in the old boy network kind of things. Many people in Cambridge--

Zierler:

What does it mean to be a Cambridge man?

McKinley:

To be a Cambridge man, yes, that’s very much an English expression. There are many people you’ll find there who are undergraduates there who then became graduate students there who then became lecturers there and spent their entire career in Cambridge.

Zierler:

They’re lifers, essentially.

McKinley:

They’re lifers, yes. And I’ve never been a big believer in that. It leads to a lot of inbreeding in the sense of an academic inbreeding, that there’s one way of looking at the world. So there’s the Cambridge way of looking at the world, which has no doubt served it very well, but my advisor came from outside that system. He had got his degree in Bristol. He spent time in his PhD in something called the H. H. Wills Physics Laboratory in Bristol, which is a very well-known one. H. H. Wills, actually, who had endowed that, also was the founder of a tobacco company in the UK, so it was kind of an interesting connection there. But the Wills Physics Laboratory was very, very good, and he had done his PhD there. He then spent some time as a young assistant professor or a lecturer in the English system at the University of Sussex, which is a relatively new university. Then he had moved to Cambridge probably—I actually don't know exactly the year, but probably the very early 1980s—to one of the new colleges that was called Robinson College. He was the person who was my Director of Studies and also the one that I did my master’s thesis with. So there’s no doubt he was the most influential person.

Another person, however, who used to teach fluid mechanics and chemical engineering at my college, was a guy called David Blackadder, and he had stopped teaching because he had become bursar of the college, kind of essentially in charge of the finances of Downing College. But he’d been a very good lecturer in the field of fluid mechanics, and so I’d used some of his notes and some of his notes that he had written. So those were formative for me as well.

Zierler:

Now when you go on for your master’s degree, my first question is, is there a senior thesis requirement for undergraduates at Cambridge?

McKinley:

There may be now; there wasn’t in those days. So it was all classwork and very much in the old style. There wasn’t even very much partial credit for work done during the semester. I think 90% of the grade came from final exams.

Zierler:

Mm-hmm [yes]. Now did you have a momentum where there was a very natural progression on to the master’s degree for you to stay where you are and just to continue working on your topic as a master’s student? Or was this a more deliberate decision on your end?

McKinley:

No, it was a very easy, very natural one because the Cambridge system—Cambridge changes slowly, and it’s served it well over the 900-and-something years it’s been going. But most of my colleagues and classmates at Downing College all finished after three years, either with degrees in math or chemistry or physics or medicine. The medics then went off and of course did their clinical work. The chemical engineers stayed on for a fourth year quite naturally, and so there was a cohort of…I think it was about 42 of us in our year. So this was the end of 1985 and going into 1986. So that cohort of 42 spread out over all the Cambridge colleges formed a natural kind of group that stuck together because most of our other friends had all left Cambridge at the end of ’85. So there were five of us at my college, at Downing College, and I’m still in touch with four out of the five of them, in fact, after all these years. So it was very much a natural continuity. Three of us lived together in an apartment or a flat, as we call it in England, off of the university. The college didn't have enough residence rooms for fourth-year students, so you were kind of living in a flat in Cambridge. Then everybody would get together to lecture. So it was really quite natural and quite seamless.

Zierler:

Was your master’s thesis a natural progression of your undergraduate studies, or did you pick a discrete topic that you had not worked on previously?

McKinley:

Yeah, you picked a discrete topic, and all the 40 of us had discrete topics. Could work for anyone in the department, but I happened to work for Malcolm, who was my Director of Studies as well. His suggestion had been… You know, I said, “I want to do something that maybe involves polymers and fluid mechanics,” and he said, “You should go down and talk to this graduate student in my lab,” who was doing a PhD with him. So I did and this graduate student was a rarity at Cambridge. He was an American who had done his undergraduate degree at MIT in chemical engineering and was now doing his PhD in Cambridge. So we would sit and talk to him and he’d tell us about MIT and about what it was like to be an undergraduate there. So that was when I really first became aware of MIT. I’d traveled to America. I’d been to America twice already in the summers of ’82 and ’85 purely as a tourist, and I’d pretty much decided I wanted to come back and spend time in the States sometime.

So that’s when I started to think about maybe applying to graduate school. The easy thing would have been to stay on and do a PhD at Cambridge and become a lifer, as you said, just stay in Cambridge. But Malcolm, having come from outside the system, encouraged me to look outside the system. I think even back in those days, maybe he wasn’t totally integrated into the system. You know, if you weren't a lifer, you weren't as embedded in the system. He spent the rest of his career there, so I think he became more and more of a Cambridge person, but at least then he was relatively new in the system. So he encouraged me to look, and he suggested three universities for me to apply to in the US.

Zierler:

Now before we get to that, what was your master’s thesis on?

McKinley:

So I can't remember the exact title now, but it was basically funded by British Petroleum (BP) and from there downstream, a chemicals business. So in the oil world, the upstream people are the ones digging holes and mining for new sources of petroleum. Much of it then in the UK in the ’80s was brought in to Scotland. The oil was taken out of the North Sea and brought into a place called Grangemouth in Scotland. BP had a large refinery there where you’d refine the oil down into other chemicals, both petroleum for sale, but also then that you used as a feedstock to make plastics. They were making polypropylene there, so they were making polypropylene from feedstocks, and it was all about the processing of polypropylene, which was already a very big material then, but went on to become the biggest single used plastic in the world.

Zierler:

Now at Cambridge for the master’s, is there an expectation that the thesis has original research or is this mostly synthesizing literature?

McKinley:

Yeah, that’s a great question. Looking back on it, it was more on… It had to have an original component, but a lot of it was an educational component of learning how to read the literature, learning how to do experiments, things like that. So you had to write a report, but you didn't have to write a paper. So my master’s thesis was never published. It was never sufficiently deep or technically deep enough to quantify as a single paper, but it formed some side avenues of this PhD student, David Mead, who was in the lab at Cambridge. It was kind of side avenues of the work he was doing. So looking back on it, it’s very different than a master’s thesis would be these days, but back then, it was much more educational component with a small original component to it.

Zierler:

Given the companies that were supporting your work in the program, I wonder if you ever considered entering industry.

McKinley:

Yeah, I did. I very seriously did until really my last year. I spent part of an internship at Shell, another big petrochemical company, in their central research section in the UK in a place called Faunton.. That was an interesting summer. I spent some time there in the summer of… It must have been the summer of ’85, but it wasn’t as original work. There was much more of the kind of big chemical process refinery tanks, things like that. It wasn’t as much of… I was clearly already getting an interest in original research, and so I didn't find it very satisfying. So after that I went off and spent, again, part of the summer with the London International Youth Science Forum and then after that finished, which finished in the middle of August, I then traveled to the US for a month and spent a month traveling around on Greyhound buses. Back in those days you could buy a one-month long Ameripass, it was called, which allowed you to ride Greyhound buses as much as you wanted. I went all the way out to the West Coast by bus and took a look at a couple of universities, very much as a tourist then. When I came back in ’86, I was like, “I think I’m going to apply to grad school in the US.”

Zierler:

Now the J. C. Platt Prize, was this in connection with your work as a master’s student or this was separate?

McKinley:

That was separate. That was… So at the college, every college in Cambridge had its own prize system. There was very much a hierarchy in Cambridge college life, which was the very, very top percentage of people got scholarships or got fellowships. Then the next group down got smaller prizes, and then there was everybody else. So I was nowhere near scholarship-level material for the first two years, but by the time of my third year, I did get a college scholarship. So that gave you prize money, and so the J. C. Platt Prize was a book prize that actually I bought a book that I still have. It’s sitting on my side still, actually. So the sticker inside that was… I bought a book called Dynamics of Polymeric Liquids, and I’ve had that. It’s a little moth-eaten now, but that was my J. C. Platt Prize in 1986.

Zierler:

Now when you decided to go for the PhD, to go the academic route, did you apply exclusively to schools in the States, or you applied elsewhere in the UK also?

McKinley:

Yeah. The UK system was very, very informal, and I think it still is to a large part. So it was made clear to you without any application needed that if you want to stay on, there’s a place. You would literally say, “There’s a place for you here for a PhD,” and you wouldn't have to apply. There would be no form, really, and Malcolm, I think, would have supported a PhD for me at Cambridge. So I could have stayed in Cambridge quite easily.

Zierler:

Was there anyplace else in the UK that would have been comparable, yet different, to Cambridge?

McKinley:

Of course, the Cambridge elitist view of the world usually was, “No, there isn't a place that’s comparable.”

Zierler:

Oxford excluded?

McKinley:

Oxford didn't have—still doesn't have—chemical engineering. It had an engineering science department, but it was much smaller. It was not its strength, and that’s really partly why I’d been steered towards Cambridge back in the day from school. So it was really Cambridge or the US for me.

Zierler:

And nowhere on the continent? You weren't thinking anywhere in the rest of Europe?

McKinley:

No. My languages were never very good. My French was marginal. My German was worse, and in the pre-Internet days, it was not so easy to do research into different universities.

Zierler:

Right.

McKinley:

So it was ones that you were aware of, and so Malcolm mentioned three places in the US that he knew people at, and then also there was Cambridge. So it really came down to one of those four places.

Zierler:

So which were they? What were the three places in the States?

McKinley:

So he knew a guy at UC Berkeley whose name was Morton Denn, Mort Denn, someone that I’m planning to do an oral history with as well, actually, who just turned 80. So he was out at UC Berkeley at the time. I had to do the GREs, and in those days, that was something that you still filled in the form, black and white pencil circled answers, and things like that. So I sent my GRE scores to Berkeley to him, to University of Wisconsin in Madison, which has a very, very strong chemical engineering department, and Bob Bird, who we have an oral history for in the Niels Bohr Library already. He was there, and then to MIT to one of Bob Bird’s students whose name was Bob Armstrong.

So Bob Bird wrote back to me very nicely, and this was in early ’86, saying, “I’m just about to retire. I’m not taking any more students, so I would strongly recommend that you go to MIT and work with my former PhD student Bob Armstrong.” So really it came down to one of two places, and I got admitted to all three. The way the UC Berkeley system worked, Mort Denn wrote back to me and said, “Well, I don't have any money for you for the first year, but if you come to California after one year, you count as a state resident.” So after your first year, you become eligible for state tuition, which of course is very, very much lower than international student tuition. So that was attractive, but I still didn't really know how to cover my first year, whereas MIT, I was able to win this thing called the Kennedy Scholarship and that covered me going to MIT. So it became a fairly obvious conclusion which way to go. I didn't visit either of them, but it became a fairly easy decision.

Zierler:

Now the Kennedy Scholarship, was this for foreign students? Who were the people that won this scholarship?

McKinley:

Yeah. So after Kennedy was assassinated in ’63, about a month after I was born, actually—so he was assassinated in November ’63; I was born in October ’63—the British people had a huge kind of outpouring of donations. I suppose the equivalent would be kind of like a GoFundMe page these days or whatever. The money was donated into a fellowship fund, and what they decided would be the best tribute would be to use that fund to send people from the UK, typically between 10 to 12 people a year, to Kennedy’s home state of Massachusetts. So you could either go to Harvard or to MIT for a year after you finished your undergraduate degree.

Zierler:

And this was available across all disciplines or was for math and science?

McKinley:

Yeah. No, it was across all disciplines, and by far the majority went to the Kennedy School of Government or things like that. So most people went for one year to Harvard to be a special student or to get a master’s degree at Harvard. There were only two of us in my year who went to MIT, and we both went to chemical engineering, in fact. So Matthew Ralph was my roommate then for three years at MIT after I got there. He was finishing his degree. I didn't know him at the time, but he was getting his degree at Imperial College in London and I was at Cambridge. So we both won them and we both went to chemical engineering at MIT.

Zierler:

Now when you landed at MIT, I wonder if you could talk on two levels about some of the cultural differences that you experienced, both as someone from England, but also coming from the Cambridge way of looking at the world to the MIT way of looking at the world.

McKinley:

Yeah. I could go on for a long while about that, so you might have to stop me on some of that because it was culturally a very, very different thing. It was fantastic to have… There were two other English students in my year, so there were three of us out of the incoming class of about 50 chemical engineers. So three of us came over from the UK. One person I knew from Cambridge, Paul Coates. He was later on the best man in my wedding, but he came over with me from Cambridge, and then Matthew Ralph from Imperial. So there were three of us, and that really helped. The three of us lived together, and so we were able to study the way the English studied, which tended to be very independent. People would work on their own. Nobody worked together, whereas there was much more of an American style of maybe working together. We didn't know that at the time, but eventually we developed a way of doing that, the three of us working in our apartment together. So that was one difference immediately.

But then also the style was much more back into weekly problem sets, so every subject we took would have a weekly problem set with an assignment. It was due next Monday and you had to hand it in, and students really took that seriously. The Cambridge system and the English system in general is much more independent where suggestions were made. “You may want to study this problem. You may want to do these old exams.” But nobody set weekly problem sets. It was all much more onus on the individual, and so that was a very different thing. So I hadn't had weekly problem sets since I’d been in high school, so it was a bit of a shock to the system to get back to that. So on one side, that was one set of things.

The other side was that the Oxbridge system had served us very, very well in terms of the analytic side of things, and so the first year of graduate classes was hard. There was no doubt it was hard and it was a lot of work, but in general, people coming from India or from Australia and from the UK system did very well. So we tended to have that kind of analytic style, whereas I think American students were much better at hands-on stuff probably. But the first year graduate curriculum, at least in chemical engineering, didn't have very much hands-on opportunity, so they were somewhat at a disadvantage there.

Zierler:

Now when you came in, was your level about the same as if you had stayed on at Cambridge? Were you sort of behind, ahead? Where were you relative to your other students?

McKinley:

Yeah. Probably a little ahead because…at least in terms of chemical engineering, not by much. But in the Cambridge system, there was no breadth requirement at all. The last time I had done a liberal arts class had been when I left high school at 18, so there was no writing, no language requirements, no humanities requirements, whereas of course, most of the American students had had breadth requirements in their undergraduate degrees. So that had naturally detracted maybe a little bit from the amount of engineering that they’d done. So I would say in terms of on the math side of things, we were probably ahead. On the basic principles of chemical engineering, we were probably about the same because we didn't start studying that at Cambridge until junior year or third year. But in terms of basic analytical ability, maybe slightly ahead.

Zierler:

Now what would the circumstances leading to your work on research that was being supported by President Reagan’s Strategic Defense Initiative (SDI), or Star Wars as we call it, how did that come to be?

McKinley:

Yeah, exactly. For me, totally accidental. Yeah, so my first year was supported by this Kennedy fellowship, and then out of the 12 Kennedy fellows, I think the 10 who were at Harvard all went back at the end of that year. That was the natural plan, that you then go back and go into the workplace or the British government or something like that. But the two who had come to MIT, we both decided we wanted to stay on—not finish with a master’s, but work on a PhD. So you had to transition to get a research assistantship. The fellowship only covered you for one year, so you need an RA in the vernacular.

So I had been working with Bob Armstrong and Bob Brown, who was another person working in the rheology area, and they were both very well-funded at the time. They had a big, big project that happened to have been funded, and it was only after I said yes to working on that project that I found out that it was funded under SDI, as it was known, or the Strategic Defense Initiative, that Reagan had announced a year or two years ago. Nominally at least, the whole area was on what were called, euphemistically, energetic materials, but energetic materials were rocket propellants and liquid rocket propellants or solid rocket propellants that were used, for example, in solid rocket boosters for intercontinental ballistic missiles or as the boosters for the shuttle.

Zierler:

Was there any component of this work that was sensitive or classified or any problems you ran into there as a foreign national?

McKinley:

Absolutely none. No. In fact, they shielded-- Both Bob and Bob (Bob Armstrong and Bob Brown)—we referred to them as the Bobs. They shielded almost all of us as students from any of that, so we were very… We were not really very aware. They didn't share what the proposal main topic was, but it was very much on the fundamentals of flow instabilities. The reason that was of interest was that if you have an instability… An instability for a fluid machination is where some nice, steady, stable flow suddenly becomes unstable. It might become time-dependent or fluctuate. But if you had an instability and you happened to be filling a rocket engine, then it might lead to things going boom. So that was the kind of fundamentals of it. But it was very, very much fundamental science. It was very much removed from the sharp end.

Zierler:

Was it also sufficiently removed where you didn't concern yourself with some of the ethical issues about putting science to use for weaponry and things like that?

McKinley:

Certainly it was so far removed that it didn't even really seem connected, and they certainly didn't share with us, “Oh, this is funded by SDI.” You know, it was like I have a research assistantship in the fundamental fluid mechanics of flow instabilities in non-Newtonian liquids, and I thought, “That sounds interesting.” It’s only after a year or two that you realize that it’s connected to that.

Zierler:

What was your reaction when you did find out of the connection?

McKinley:

It was so fundamental science and it was so unrestricted and open that I had very little problem with the ethical difficulties. It was probably-- I think to most scientists at the time, it was realized that the end goal was probably 20, 30 years or more away. It was very much a mechanism for funding fundamental research rather than a mechanism for developing means of delivering nuclear weapons.

Zierler:

Right. So when you say fundamental research, you mean that this research could be used for things that had no military component whatsoever.

McKinley:

Precisely. Yes, and it was really to try and understand fundamental physics. So for me, that outweighed any other… You know, if I had been asked to sign… If there had been any confidential component or any classified component, I think (a) I would have had a much bigger reservation with it, but I think MIT wouldn't have allowed such research on campus anyway. So any component that was like that was removed from these kinds of fundamental programs. I’d say… I’ll just want to add one last thing that was convolved into all of that. I’d come over. Thatcher was prime minster in England and Reagan was president in the US, so it was very much that mid-’80s, late ’80s, end of the Cold War kind of thing. Probably as I started to become more and more aware that this work was funded through SDI, which was probably ’88, ’89, this was right as in fact the Berlin Wall was coming down and communism was ending. So any natural concern that I had actually seemed to go away quite naturally at that time.

Zierler:

Yeah. It was kind of after-the-fact at that point, yeah.

McKinley:

Yeah.

Zierler:

Now the interdisciplinary Program in Polymer Science and Technology, was this created brand-new during your time or it preceded you by a few years?

McKinley:

Yeah. So I have to mention… The other person that I got to know when I first arrived at MIT-- Because I came on a Kennedy fellowship, they said, “You don't have to join… You're not joining a research group straightaway, so here’s going to be your academic advisor,” and it was a guy called Robert Cohen, so another Bob.

Zierler:

Three Bobs.

McKinley:

Yeah, Bob Armstrong, Bob Brown, and Bob Cohen. I didn't know Bob at the time, but he wrote back to me. This is in the days pre-email, so I got a letter before I came to MIT that said, “I’m starting this new program.” Bob Cohen had actually been a post-doc at Oxford in the 1970s, so he is very much an Anglophile. He’d spent a very, very nice time doing polymers as a post-doc in the Engineering Science labs in Oxford. So he wrote to me and said, “I’m starting this new program. I see your background, your interest in polymers and rheology, and I think you’d be a natural fit for this program. Are you interested?” I hadn't heard about it. You know, it’s not something that I’d seen anything about, but he included the catalog. I thought, “This looks very interesting,” because I knew I liked a little bit of physics. I liked a little bit of chemistry. I liked a little bit of fluid mechanics. I wasn’t aware of interdepartmental programs. They were relatively a new thing at MIT. But in MIT language, a program is something that isn't a department, so it doesn't have undergraduates, but a program can admit its own graduate students.

So they were looking for people who were suitable for it, but they were also picked people who had already been admitted by a department. In that way, that was a safe way of saying, “The people who are coming in have already been vetted by existing departments at MIT, but it looks like they have the right interests.” So it probably involved Bob scouring through goodness knows how many admitted student folders, finding six of us. So there were six of us who came in in September ’86 who were the very first inaugural class of PPST, as it was called then.

Zierler:

Mm-hmm [yes]. So besides chemical engineering, where were some of the other students coming from?

McKinley:

Yeah. Let’s see. So there were six of us altogether, and I think there were two of us in chemical engineering, so myself from Cambridge and then Aluj Bellare who came from one of the Indian Institute of Technologies. So he’d done an undergraduate degree in chemical engineering there. And then one person in mechanical engineering, one in chemistry, and… Actually, I guess two in mechanical engineering and then one in material science and engineering.

Zierler:

Now was the idea to work on projects where everybody coming from their home discipline would have something unique to offer? Was that the idea?

McKinley:

Yeah. The idea was to form a small cohort of people who had different original strengths and put them together in a program, but rather than just do classes in, say, chemical engineering, our curriculum involved a little bit of chemical engineering, a little bit of material science, a little bit of mechanical engineering, and a little bit of chemistry as well. It was perfect for me. I didn't know that’s what I had been looking for. Clearly Bob realized that, but it was someone who wasn’t really completely a chemical engineer but wanted to still do a bit of physics, wanted to do some fluid mechanics, wanted to do a little chemistry. So it was really a fantastic fit for me.

Zierler:

Did the students set the curriculum or there were professors that were doing oversight at that level?

McKinley:

No. They did the oversight. They constructed it and they gave us very limited choice, actually, because it was basically formed by a bunch of faculty who had interests in this area, but they didn't have the resources to set up an entire set of new classes. So it’s like, “What classes do we already have that if we pull a class from chemistry and a class from mechanical engineering and a class from here, put together a coherent whole?” We certainly didn't know what we were looking for. They were the ones who knew what made a good curriculum.

Zierler:

Now your work in this program and your budding dissertation research and ultimate project, were these something that you did on separate tracks or these were interrelated projects?

McKinley:

Yeah. So the way a PhD worked at MIT then, and still largely does, is you come in in the first year and you do primarily coursework, and each year you do slightly less coursework and more and more research. So the first term was all coursework for us, and to make sure that you didn't get sidetracked or streamed into one thing straightaway, they actually had a form that you had to sign where you had to go around and talk to five different professors about their research. So you’d make an appointment and you’d go in and say, “Tell me about research in your lab or in this lab.” The great thing for the PPST students is that it could be any professor who was affiliated with a program. So even though I’d been admitted in chemical engineering, I went to talk to professors in material science and in mechanical engineering and talked to them about their research. Then after an hour of talking, they’d sign your paper that said yes, you’d come and talked to us. Then they would have a choice to say, “Yes, there’s an opening in my lab,” or “No, there’s not an opening. I think this is a good fit for you or not a good fit for you.”

So I very nearly… I took a class by a professor who is now a colleague, Ioannis Yannas who worked in using polymers for artificial skin. He was very interested in skin grafts and developing what are now called scaffolds for both seeding epithelial skin growth or nerve growth. It was something I’d never seen before, but I did a little bit of biology. I liked that. I liked the fluid mechanics. It just involved a little too much histology for me at the end of the day. A lot of it was implanting things onto the backs of guinea pigs and hamsters, letting them develop scar tissue and then euthanizing them and looking at ingrowth and whether the polymer was biocompatible. That bit of it wasn’t a good fit for me, but I very nearly did something completely different just because you’d come to MIT and your eyes were opened to topics that you’d never even imagined. But in the end, I’d signed up for five professors, and one of them turned out to be Bob Armstrong, who was this person that I’d been steered to by Malcolm the year before.

Zierler:

Right. So what was the process of settling on a dissertation topic? How did that work?

McKinley:

Yeah. You went to talk to the professor, so you went – I remember very little of that initial conversation, actually. I really don't remember too much of it at all, but you’d go and talk to the professor. He would describe, you know, what their vision was. “Hey, we have this project,” and he certainly didn't say it was an SDI-funded project like you had described. “We have this problem,” or “There’s this flow instability. Why don't you come along to our group meetings?” So I’d go along to their research group meeting, listen to one of their student’s projects. I think students these days are very much more deliberate about their choice, and they really do spend some time interviewing faculty members and going and talking to graduate students about what it’s like working with Professor X or Professor Y. It all seemed to happen somewhat naturally for me. I nearly had had this left-field excursion in going to work with Professor Yannas, but it seemed to be a natural expectation. I liked this area. I liked Bob Armstrong a lot, and I liked polymers. So it seemed to happen quite naturally without me really being as aware of the process as maybe students are these days.

Zierler:

What was the process in terms of identifying a dissertation topic of thinking about work that had not yet been done but needed to be done, identifying that sweet spot? Are you consulting with professors? Are you really deep into the literature yourself? How did that process work?

McKinley:

Yeah. I would say that it was very, very heavily steered by the professors. I was not very aware of the literature at all, but I knew what I liked and I knew what I’d done in my master’s thesis. I’d done this work on polymer processing and I’d enjoyed the experimental side of it. I think I got that from Malcolm Mackley. So Malcolm was an experimentalist. He liked to build hardware. He enjoyed cobbling together new instruments from things in the lab, and I’d enjoyed that. I was not very good at electronics, but I knew a little bit about data acquisition, all self-taught from building a computer when I’d been at Cambridge kind of from a kit computer. So back in those days you could order the parts and get them and put them together, so I knew very, very little about that. But I liked the experimental side, and I was probably better at that than the computational side.

So Bob and Bob had a program. It was largely theoretical because both of them came-- One of them came from a computational fluid mechanics background and the other person came from a kinetic theory background. But they knew they needed an experimentalist to generate data that they could then compare with their computations. So they had a small lab with a couple of students in it, and they had suggested to me, “Go and talk to those students in the lab,” very much in the way that I’d gone to talk to this student at Cambridge.

Zierler:

Right.

McKinley:

So it kind of happened naturally. They steered me in that direction, and clearly it was what I wanted to do and so I said, “Yeah, I’ll be happy to do an experimental program to generate data that might serve a role for some of the theoretical side.”

Zierler:

So I’ll test your memory again—the title of your dissertation.

McKinley:

Was something like… I think originally it was longer than the final one. Originally it started with “Experimental investigations of…” but we got rid of that, and then it just became “Nonlinear dynamics of viscoelastic flow in complex geometries.”

Zierler:

What did you see as your primary contribution to the field, and then what was the field that you were contributing to?

McKinley:

Yeah, so I think I saw it as the first, or one of the first at least, really careful studies that applied some of the tools of nonlinear dynamics which were developed a lot in the 1980s. This had been the birth of chaos and the ideas behind nonlinear things leading to chaos and turbulence, and taking some of those ideas that had been really well-developed in other fields and applying them to the polymer…or the rheology field. So both my advisors were very good, very widely read, and knew topics in other areas, and so they were able to say, “You should learn a little bit about this. You should learn a little bit about that.” It really… I think for someone like me it was great because it involved just enough math and just enough physics and just enough experiment that I could do all of those well and maybe do them slightly before other people did in the field.

Zierler:

So it sounds like there was a real interdisciplinary approach to your dissertation. I wonder if you were drawing on the program to have that perspective.

McKinley:

I guess in retrospect, definitely I was. I think so. I think I didn't really know that at the time. You know, a PhD is a time when you’re really, really deeply down, nose first into something, and so I think in retrospect, certainly it was great to have that training. But I don't think I was aware of that at the time. I wasn’t very intellectually self-aware of such things, you know. It was much more about getting the damn experiments to work and middle of the night getting things running and things like that.

Zierler:

Yeah. Who was on your committee?

McKinley:

My two joint advisors were Bob Armstrong and Bob Brown, so they were both co-supervisors. Then in those days, you were beginning to have--

Zierler:

Was that unique at MIT to have co-supervisors?

McKinley:

It was beginning to become common. They had formed… You know, they’d both been hired separately in the ’70s. They’d each had their own students, and they probably had started working together right at the end of the ’70s and the early ’80s. So it was beginning to become common. I think they were far, far ahead of the curve in terms of the number of students that they had together. They probably had about 30 graduate students together, PhD students together, which was really unusual. They formed a very natural connection because they both had complementary skillsets. One was a computational person, one was a theoretician, and they worked really, really well together. So that was unusual, and still I don't think I’ve advised that many students with anyone. So that’s still a rarity. But having co-advisors was beginning to become more common, and particularly in these interdisciplinary programs where one person would have a strength in physics and another one in chemistry. So in PPST, it was quite common to have co-advisors. So I didn't see anything negative about that. Then the third Bob, Bob Cohen, was the third member of my committee. So it was all Bobs and me.

Zierler:

No outside reader. They don't do outside readers at MIT.

McKinley:

No, don't do outside readers in the Cambridge system…sorry, in the MIT system.

Zierler:

Well, the Cambridge, Massachusetts system.

McKinley:

Yes, yes.

Zierler:

You’re still in Cambridge. [Laughs]

McKinley:

True, true. Yeah.

Zierler:

So what was the date? When did you defend?

McKinley:

I think it was May 22. It was certainly the third week in May in 1991.

Zierler:

Okay, 1991.

McKinley:

There were three of us who were very, very close in the same group, and we actually defended on like the Tuesday, Wednesday, Thursday back-to-back-to-back. So there were three of us who all came up for graduation at the same time, and I’m still very, very close friends with both of those other two people.

Zierler:

Now leading up to and then shortly after the defense, I mean the same question about at the end of your master’s degree. At this point, were you academic faculty position all the way, or were you still considering industry or a consultant to government work, things like that?

McKinley:

I tell you, until probably about February, it had been industry all the way, I’m pretty sure.

Zierler:

Of ’91. February ’91.

McKinley:

Of ’91, yes.

Zierler:

Really? Industry all the way.

McKinley:

Industry all the way. Actually, maybe a little earlier than that. Maybe late fall of 1990. Then one of the other three-- So the three of us who graduated—a guy called O’Callum, and Paul Norvi, and I were three people who were all working on topics for the Bobs, totally different topics, but spending a lot of time together and a lot of late nights writing. Back in those days, people didn't have your own computer, so to write, you were basically… We had one Mac that was shared between everyone in an office of eight, and so you take turns to say, “I need to spend two hours” using what was in those days Word Perfect.

Zierler:

And they’d better be a productive two hours, too, right? [Laughs]

McKinley:

It had to be a productive time with something like that. So those two were both actually using this program that I didn't like called LaTeX at the time because they were more computational side. So they could work independently, but then to actually do the typesetting, we had one laser printer in the office, which I think when we had got it, the thing weighed about 400 pounds, and I think it cost $5,000 in 1989 money. We were one of the rare groups. Because we had Star Wars money, we had the money to have a laser printer, so it was a rarity. The plots for my thesis were all still done with a pen plotter kind of thing, so it was still… If you wanted color, it had a mechanical pen plotter that we used. That’s a digression, but anyway. [Laughs]

So we were all in it together and we were all trying to think about what to do. We’re all applying for jobs. DuPont and Dow were both very, very big hirers in the chemical engineering department at MIT, so I had an interview with DuPont and I got an offer from them. I had an interview with a company called W. R. Grace and I got an offer from them as well. DuPont to me seemed like a perfect job. It was at the experimental station down in Delaware, and it involved polymer processing and rheology and all the things that I liked, so that seemed like a really natural fit, apart from two things. One was my girlfriend (and actually my fiancée at the time) who was still in Boston and had another year to go, so it was going to mean living apart for a year. She was at Boston College doing an undergraduate degree, so she was four years younger than me, but she still had one year left. So that was one reservation. And then I had enjoyed… I’d been a teaching assistant for one of the Bobs’ classes, and I’d really enjoyed teaching and really enjoyed the explanation part of things and was doing that informally with other people in the department, kind of within the PPST interdisciplinary thing. So I started to get interested in maybe applying for teaching and so just looked at a couple of jobs. I think my advisors steered a couple of announcements towards me and said, “You might want to consider applying for this.” So I applied for two positions, one at Santa Barbara and one at Harvard, and that was it.

Zierler:

Now before we get to that transition, I’m curious what was attractive to you specifically about a place like DuPont. So for example, when you talk to physicists who worked on semiconductors and things like that and they worked at a place like Bell Labs and they talk about it in the fawning terms of, “This was a place where the funding was tremendous and the collaboration was great and the instrumentation was great. You could really do pure science and not have to worry about…” Was that your basic idea with a place like DuPont, that you could really do real science there and not have to worry about economic corporate considerations?

McKinley:

Yes, exactly, exactly, except I might say rather than pure science, maybe I’d say pure polymer engineering or something like that. They were making a huge amount of money on advanced materials. Everything from Kevlar to Spandex at the time were two of their advanced engineering polymers. There was everything from the basic chemistry of it to the processing of it to the fiber spinning of it. You know, I saw a Kevlar spin line while I was there, which was just an amazing process to me of this rigid rod polymer dissolved in fuming sulfuric acid at 100°C coming out of the spin tower into a vat of nonsolvent which was water and steaming and making micron-sized fibers. Bulletproof vests at the time seemed like something unbelievable, so sort of--

Zierler:

This is like kid in a candy shop kind of thing, it sounds.

McKinley:

It was a kid in a candy shop for me, so it was great. But then I had convolved… I’d also weaved into… I also did visit Bell Labs in February of 1991 as well because as you say, people will talk in fawning terms about how wonderful it was and I--

Zierler:

Although by ’91, that was probably on the downswing at Bell at that point.

McKinley:

That was exactly it. There was a fantastic group of people there led by Ron Larson, who is still a very, very good colleague and friend of mine at the University of Michigan now. Susan Muller, who had been in the same group as me who had been a post-doc there and had gone to Schlumberger. Eric Shaqfeh, who is now a professor at Stanford. Glenn Fredrickson, who is now a professor at Santa Barbara.

But it was the beginning of the end. ’91, the writing was already on the wall and people were beginning to leave. So even though I did get an offer as a post-doc, I’d say within a year or two of that, Eric had left for Stanford. Susan Muller had left for Berkeley. Ron Larson was one of the-- Glenn Fredrickson left for Santa Barbara. Ron was probably one of the last people who stayed on at Bell Labs until maybe ’94 or ’95. So it was clear that those golden days of unlimited money and the chance to work on anything you want were almost gone, whereas it seemed like it was still there for someone like me, at least, at DuPont.

Zierler:

Well, at DuPont there was no anti-monopolistic issue, I assume, right? They didn't have that looming threat.

McKinley:

No. No. Dow and DuPont were both too big to fail in the current terms, and they were giant. They were healthy competitors and both hired huge numbers of chemical engineers.

Zierler:

But ultimately you had too much teaching in your blood and that’s the way you went.

McKinley:

Yeah, I think so. Harvard made me an offer and it gave me a chance to stay in Boston. I still remember one piece of advice that Bob Brown had given me. He said, “If you do want to try your hand at it, it’s almost impossible to go from industry back into academia. It’s much easier to go from academia into industry.” So he said, “If you want to do it, you should try it now.” So I said, “I’ll try my hand at it.”

Zierler:

Right. Now you had… You were named as an assistant professor, but you had a named chair, the Gordon McKay Chair of Engineering Sciences. Did anybody take you aside and explain to you the politics of being a tenure-track professor, but somebody who held a named chair and exactly what that meant, or did you have to sort of figure that out on your own?

McKinley:

You kind of figured it out on your own. The way it works, Harvard has a unique system, and still does, that its management system, they call it ETOOB, which stood for Every Tub On its Own Bottom. The idea was that the School of Engineering had an endowment and they had only used it for itself. The School of Business, the school of…the Management School, which means that you have some fantastically rich or affluent schools at Harvard like the Management School. Then, as you might imagine, the School of Education and the Divinity School have much smaller endowments, but there was very, very little sharing of money at the central administration level. There was some. It was basically a tithing system where they had to pay a small amount into central administration, but the School of Engineering—back in those days it was called the Division of Engineering—had its own pot of money that had been left to it by Gordon McKay. So almost every professor had a named chair so that we had access to money from that endowment.

Zierler:

Money for your own research, your own lab work.

McKinley:

Yes. Yeah, and it wasn’t an unlimited amount, but when they gave you a startup package, they’d say…and I don't even remember how much mine was now, very small by modern terms. But there was a startup package, and presumably they also paid my salary out of that endowment money as well. So there were a number of Gordon McKay professors.

Zierler:

Now it’s a much shorter travel time from Cambridge to MIT, but I want to ask the same question of cultural differences coming from MIT going to Harvard. What were some of the different ways that each of the institutions did things?

McKinley:

Yeah. Going to Harvard was a little bit like going home to Cambridge UK in that sense.

Zierler:

Oh, interesting. Interesting.

McKinley:

In fact, the year that I’d arrived in Boston in 1986, it had been Harvard’s 350th anniversary, so we had gone up to a couple of events there even though we were down at MIT. MIT really did feel very much like an engineering school at the time, and Harvard felt much more home. It felt much more like Cambridge. And of course, 10 out of the 12 Kennedy scholars were all up the road at Harvard, and so we’d go up to events with them. In many ways, it always felt… Well, Harvard’s a bit more like what I imagined it was going to be. MIT at the time was a technical school. It was very much “the institute”. It’s, of course, changed a lot in the last 30 years. It now competes with Harvard and Stanford and Princeton as a top-ranked university, but in the time it was very much a technical school only.

So going back to Harvard really felt a little bit much more like going back to a Cambridge-style education. It was broader, maybe more science-focused and less engineering-focused, so it was harder to be an engineer there. In fact, many people didn't even realize that Harvard had engineers. So you’d go to a faculty meeting and you’d sit down next to someone who was an economist or an English professor and they’d say, “What do you teach?” and I’d say, “Oh, I’m in engineering.” They’d say, “Oh, we have engineering? I thought they did that at MIT.” So that has changed a lot now as well, but at the time, it was a fairly small program.

Zierler:

When you started in 1991, what were the expectations in terms of teaching and research? How were you supposed to split your time?

McKinley:

Yeah. I still remember you’d arrive, and their mentoring system was not really very well developed in those days. You were kind of on your own. But it was very clear that yes, you had to teach and you had to do an okay job of teaching. But the only way you were going to get tenure, if at all, at Harvard was going to be through research. So it was basically do what you need to do. You've got to learn to write grants. You’ve got to figure out good ideas. You’ve got to hire graduate students, and you’ve got to publish or perish for sure.

Zierler:

Did you take on graduate students right away?

McKinley:

Yes, almost immediately. So the first year when I arrived in the fall of ’91, I had no students. I was just teaching, but I was teaching first-year graduate fluid mechanics that year. So that gave me a great chance to meet all the incoming first-year graduate students and attract students to my lab, and they started by January of 1992.

Zierler:

Now when you achieved tenure in 1995, is it just a new name for the chair or are you switching departments altogether? The John Loeb Chair of Natural Sciences. Does this mean you're switching departments?

McKinley:

So in the Harvard scheme of things, that was an associate professor, but at Harvard, associate professors are not tenured. So that was a non-tenured position for me.

Zierler:

Oh.

McKinley:

So after three years, they would have kind of a mid-tenure-track review and you would either continue as an assistant professor and leave or they’d promote you to associate professor without tenure. But when you get tenure in Harvard, Harvard does everything at once. When you get tenure at Harvard, you become full professor and everything, and actually, Harvard also has this feeling that if you don't have a Harvard degree, the only people that should be tenured at Harvard should be having a Harvard degree. So they give you an honorary master’s degree from Harvard if you don't have one as well.

Zierler:

[Laughs] Wow.

McKinley:

So anyway, it was an associate professorship without review, and it was--

Zierler:

This is a promotion, though. This is undeniably a promotion.

McKinley:

Definitely a promotion, undeniably a promotion. So yes, that was ’95, and it came from within the School of Arts and Sciences. So the reason it was called the John Loeb Professor, Loeb House…the Loeb name goes back to the very founding of Harvard. So it was a different tub of money standing on its own bottom, and so now my salary came from there. But it came from the faculty of Arts and Sciences as a whole rather than from just the Division of Engineering.

Zierler:

Did you interpret this as a positive sign toward tenure or not necessarily?

McKinley:

No, I think I took it cautiously optimistic. It was a sign that things were on the right trajectory.

Zierler:

And then what were the terms in 1996 when you decided to become a visiting fellow at the Isaac Newton Institute?

McKinley:

Yeah. I’d always had a very, very good connection with the Welsh rheology crew, so there was always a very strong activity in rheology in Wales at the University of Aberystwyth and… Actually, can I just pause very briefly, David? I’m sorry. I’m going to need to pause just for a moment.

Zierler:

Yeah. Take your time.

McKinley:

Okay. Hold on. I’m going to pause the recording as well.

Zierler:

Okay.

McKinley:

I’ll be right back. [Interruption] Hello, David. How are we doing?

Zierler:

Oh, great. Okay.

McKinley:

Sorry about that.

Zierler:

No worries.

McKinley:

Very, very, very sad. My daughter’s home and her cat is dying.

Zierler:

Oh, no.

McKinley:

So they’re just taking the cat off to the vet, unfortunately. It’s an older cat, an old cat, but had it for five years or so and so a little sad.

Zierler:

All right. Well, let’s resume here. So we’re talking about the circumstances leading to your visit to the Isaac Newton Institute and your close connections with the Welsh rheology world.

McKinley:

Yes. So they had organized, in 1996 together with someone from Cambridge, this meeting called Dynamics of Complex Fluids at something called the Isaac Newton Institute, which was one of these kind of emerging institutes that had short programs, six-month programs, focused in different areas. This was largely through money that had been given by Trinity College in Cambridge where Newton had been a Fellow, and so fluid mechanics was a natural topic. Even though many of the topics were much more applied math, this program was going to be a six-month focused program organized by three people: Ken Walters from the University of Aberystwyth who really became kind of an informal mentor to me over the years. And a guy called Anthony Pearson from Cambridge who had been a professor at Cambridge, then a professor at Imperial, and was now at a company called Schlumberger in Cambridge. And then a third person, Tom McLeish, who had been at Cambridge at the same time as me in physics. He was about two years older than me, but I hadn't known him then because I was in engineering and he was in physics. He was a professor up at Leeds up at the time. So the three of them were organizing this program.

I really wanted to go, but of course I was non-tenured. I was in the tenure track at Harvard and so working towards tenure and teaching. But Anthony Pearson had done a master’s degree at Cambridge back a long time earlier, so he had a reputation or a connection to Harvard, and he was able to call up the dean and say, “Look. This is going to be a very good thing for Gareth to come to this.” I always described it as like being a post-doc with about 20 post-doctoral advisors. I was a very young person. There were only two non-tenured people there. Everybody else was kind of tenured professors using sabbatical time to go visit. So it was an interesting time for me, but totally invaluable in terms of connections and interdisciplinary ways of thinking about things again.

Zierler:

Now just to skip ahead—I want to get back to 1996, but given the fact that you're back at MIT, are you leaving for the Isaac Newton Institute thinking that you're not going to return to Harvard? How does that play out?

McKinley:

No, I was very much leaving from Harvard and thinking I’m going back to Harvard. So I was very much going back to Harvard with the idea that the next year (in ’97) the tenure process would be starting. So the goal was to go make as many connections, write as many papers as possible, and do as much good stuff as I could so that people would know me when they were writing tenure letters the next year. But at the time, MIT was not really on the horizon at all.

Zierler:

What kind of work were you doing at the Isaac Newton Institute? Were you in labs at all or this is mostly…

McKinley:

No.

Zierler:

Not at all.

McKinley:

No, that’s a great question because the Isaac Newton Institute is really affiliated with the faculty of mathematics there, so it was really all people doing either theory or writing papers for numerical codes and things like that. So I was surrounded by a bunch of people who may have had experimental activities, but were primarily interested in the modeling side of things. We’d happened to have done… I’d had a fantastic post-doc, Peyman Pakdel, who’d been in the lab with me the year before and had done a fantastic series of experiments with a lot of data. It needed some time to sit and mature or ferment and try ideas out on things, look at the data, try bouncing ideas out on other people. So the Newton Institute was a fantastic place to try those kinds of ideas out and raise a trial balloon and have people take potshots at it.

Basically, every afternoon, usually two or three times a week, there would be an informal seminar over tea, of course, being in England. So people would have a cup of tea. You’d give a seminar with an idea and people would then critique it or comment on it or say, “Have you thought about this? Have you thought about that?” So Tom McLeish was there working with Ron Larson on an idea associated with branched polymers which led to a theory called the pom-pom theory, which was hugely successful. So I got to see that born bit by bit. You know, every week there’d be a little bit more to the theory, or another hole in the theory would be nailed down or resolved. At the same time, similarly we were thinking about analyzing this data on flow instabilities that we had taken.

Zierler:

What is the pom-pom theory?

McKinley:

Pom-pom theory is a theory for branched polymers like polyethylene. So if you have a long chain that has branches on it, those branches may also have branches on it. The analogy was essentially thinking like a cheerleader having two pom-poms that they were shaking and that these shaking pom-poms were these fluctuating ends. They were thinking about it that way, so it became known… Now there were all variants of it. There was pom-pom and then since Ron Larson was involved, there was a slightly different variation that was known as the Ron-pom. Then Tom McLeish was the other person, so there was the Tom-pom…all these variants.

Zierler:

Of course. [Laughs]

McKinley:

Every week someone would point out a totally legitimate hole in it and say, “Well, this theory predicts this, but that’s wrong.” But you’d see it was really a great… For me, it was a great time to see how the pudding got made, if you like. You got to see how a theory was constructed. You know, it’s not something that someone just goes and locks themselves away and out comes this finished theory. It really was very much something that you…a collaborative thing where you try things out. There were blackboards everywhere in this. There were blackboards in the lift. There were blackboards in the men’s bathroom, and so people would be scribbling ideas on these things all the time. So we worked on a scaling theory associated with how curved streamlines affected flow instabilities and flow stabilities, and that work was really borne out of trying it out on people while we were there.

Zierler:

Now what were some of the end products of the collaboration? Were you writing papers mostly? Were these presentations at conferences?

McKinley:

Yeah. There was an end product that they had committed to which was funded by Unilever and the Royal Society that was a workshop at the very end of the six-month program that was quite widely advertised and quite widely attended by people from… The Indian Institute of Science was also somehow involved in organizing it, so it was the Royal Society, the Indian Institute of Science, and Unilever. So it was a very high profile flagship workshop that a book came out of, and everybody had contributed extended abstracts or short papers to that.

But really, for me the outcome was a couple of papers, but one that really had an impact was one on… It was called something like “On rheological and geometric scaling of flow instabilities.” It really had been a chance to pull together ideas that had come out of my lab from people like Peyman Pakdel and another former post-doc, Alp Öztekin, that we’d worked on for the last three or four years. It was a chance to synthesize it all and put it together. It wasn’t really a review paper; it was more original work than that. But that was really, for me, the primary outcome that summarized things I had done.

It also really steered me in towards things that were going to take a big priority in my life for the next four years because I met a Russian scientist who was there at the time named Vladimir Entov, or ‘Yentov’ [changes pronunciation] as it was pronounced there. He was someone who… You know, the Soviet Union had, of course, kind of collapsed by that point, but he had been able to escape. He was an academician from Moscow and he’d been able to escape partly and spend time at Cambridge working in DAMTP with a guy called John Hinch. So the two of them were working on a theory together. I got talking to him a lot, and then we went back. When I went back to Harvard, I started doing some experiments to try and work on matching some of the ideas that they had developed in the theory.

Zierler:

Now this was designed to be a one-year program only? Was there a renewable aspect to it?

McKinley:

It was a six-month program, so it was just six--

Zierler:

Oh, six months.

McKinley:

Yes. So six-month program conceived as a standalone thing. Basically, we-- I had not been involved, but they had written a proposal for six-month funding and some support and residential support for people. But then there was a ten-year reunion, so in 2006 there was kind of a program. It was viewed as a very successful six-month program at the Newton Institute, so they had kind of a ten-year reunion in 2006. But it was really conceived as a standalone thing, but some quite substantial work came out from it.

Zierler:

Now going in with the goal of making these connections and a name for yourself and making this strength in your case for tenure at Harvard, what unfolds that leads to you returning to MIT in 1997?

McKinley:

Yeah. Totally unbeknownst to me, really, there was a faculty search in ’97 at MIT in mechanical engineering. The tradition at Harvard had not been strong in terms of getting tenure, to the point where someone who shall remain nameless… I’d gone to give a talk at some point, and he kind of said, “How are you enjoying your seven-year post-doc at Harvard?”

Zierler:

Ooo. Ooo.

McKinley:

Because the expectation was that no one would ever get tenure. The last person who had been tenured when I arrived there… When I arrived in ’91, the last person who had been tenured had been tenured in ’77, so it had been 14 years without anyone being tenured.

Zierler:

So you knew this going in and your goal was to break the mold, essentially? Was that the idea?

McKinley:

No. My goal was to stay in Boston because that’s where my fiancée was and teach to the best I could and get a good job somewhere else at the end of six or seven years. There was a guy who had been hired two years before me who had come from Caltech who was a fluid mechanician, a guy called Howard Stone who is now at Princeton, but at the time was at Harvard. He was a fantastic guy. The two of us used to joke that we were the chemical engineering department. We were the only two people in the Division of Engineering who had degrees in chemical engineering. But the dean who had hired us and the senior faculty were very serious about saying, “No, we’re trying to change,” and that there’s a much better chance of getting tenure here. But still it was definitely viewed as an uphill battle because Harvard does typically use the star system. It likes to go out and hire superstars, and so people who are already hired there didn't have any advantage. It wasn’t like there was a tenured slot at the end of it for you. There was a tenured slot, but they were going to hire someone and your name might be on the list, but it may not be on the list. So the goal was not to get stressed about that, but to do the best you could and take them at face value, and if it didn't work out, get a good job somewhere else.

But then in ’95 Howard did get tenure. I think it must have been about 1995, and so the year after that, another person got tenure in robotics, a guy called Rob Howe. So it looked really good. It looked like I was going to go back and at least be seriously considered for tenure. I gave a talk at MIT, and so MIT was looking for someone and they said, “Would you be interested in moving back to MIT?”

Zierler:

Now when this opportunity came up and you considered moving back to MIT, were you still holding out the possibility that the tenure opportunity at Harvard remained open? Or did you feel at that point like that door had closed and this was really your best opportunity moving forward?

McKinley:

No. I really struggled with the decision. So MIT made me an offer and--

Zierler:

But they made you a tenured offer, right?

McKinley:

No. At the time it was non-tenure. Initially it was, “Would you be interested in coming here without tenure?” So Ken Walters, who really had served kind of as an informal mentor…You know, I talked about this with Anthony Pearson and Ken who I’d got to know very well at the Newton Institute, and they said, “You should… If they want you, if they’re serious about it and they want you, then you should ask them, ‘I’d be interested in moving, but only with a tenured offer.’”

So I went back to them with that and they thought about it. The department head at the time was a very—I don't know what the right word is—very forceful and strong individual named Nam Suh. He was the head of mechanical engineering and really knew how the system worked and knew how to operate in the MIT system. He said, “Okay. I’ll go ahead and do it. I’ll do the legwork,” which of course there’s a lot of legwork in making a tenured offer. But he said, “I’ll do it, but only if you give me your word as a gentleman that if I make you a tenured offer that you will come.”

Zierler:

And not use it as leverage, essentially.

McKinley:

Right, exactly, which is of course unfortunately common in the academic world. People do do that sometimes. So I gave him my word. Of course, nothing was written down, but I said, “Okay. I’ll do that.”

Zierler:

[Sneezes]

McKinley:

Bless you.

Zierler:

Thank you.

McKinley:

Hopefully that’s not COVID-19.

Zierler:

I hope not! [Laughs]

McKinley:

That’s a joke that may not age well, but we’ll see.

Zierler:

[Laughs]

McKinley:

I guess I’m telling this for posterity. It’s the kind of thing that I haven't really talked very much about, but I went back to Harvard and said, “I’m going to leave. They’ve made me a tenured offer.” The dean of Harvard said, “Well, we typically don't respond to such things,” so I said, “That’s fine. I understand. I’m telling you that they’re considering me for a tenured offer.” When they came back and did make me a tenured offer, Harvard, to its great credit, then very, very quickly organized a tenure review committee, was able to run around and ask whoever they asked—I have no idea who—and get the letters that they needed. They said, “Don't make any decisions. Don't say yes or no. Give us six weeks,” and six weeks later they came back and made me an offer to stay at Harvard.

Zierler:

But it was kind of irrelevant because as a gentleman, you weren't going to take that offer anyway.

McKinley:

Precisely. But it caused… As you might imagine, it was a place that I’d put six years of my life into and I really, really enjoyed my time at Harvard. The dean at Harvard really wanted me to stay and so they… You know, they wanted me to stay. If they’d done that at the very beginning and I hadn't said yes to Nam Suh, I hadn't given him my word, I probably would have stayed at Harvard because that’s where my lab was. Everything was set up. It was going to be a great place to spend a career. But at the time when he said, “Okay, I’ll go back and… I’ll go and try and get a tenured offer for you,” Harvard had told me, “No, we don't respond to such things,” which was natural and expected. I’d given him my word, so I went. So I kept my word and I moved to MIT. At the time, I felt horrible about leaving my colleagues at Harvard, but you realize very quickly that the world’s a bigger place. I thought, “Oh, they’ll never talk to me again,” but that wasn’t the case at all.

Zierler:

And I mean certainly you’re essentially across the street, so to speak, anyway, right?

McKinley:

Yes.

Zierler:

I mean it’s not that far of a move.

McKinley:

Metaphorically it’s across the street, and it’s only two subway stops in reality. So it was pretty easy to go backwards and forwards, and I stayed very good friends with people there over the years. Howard Stone stayed there for at least another decade after that, although eventually he moved to Princeton.

Zierler:

Now when you move back to MIT, you're going to mechanical engineering, so is this a different department entirely from where you graduated?

McKinley:

Different department entirely, and if I’d probably… If I’d only been a chemical engineering graduate student, that would have been probably either an impossible or certainly an improbable move. But having been in an interdisciplinary program, I’d taken some classes from professors in mechanical engineering, particularly Ali Argon and Ioannis Yannas, who I’d nearly ended up working for. So I was at least a little bit of a known quantity in mechanical engineering. Their feeling was that chemical engineering—this was now late ’90s. Chemical engineering was really evolving heavily in the biological and biomolecular and bio direction, whereas mechanical engineering had been viewed somewhat as an unchanging field and was also now trying to evolve into non-Newtonian fluids and more complex materials and things like that. So departments were moving their interests, and I guess this was a strategic area of interest for mechanical engineering at MIT.

Zierler:

Now in terms of switching departments, were you able to reconstruct your lab, pick it up and move it to MIT, or did you create something out of whole cloth? Also, did you bring any graduate students with you?

McKinley:

I did. I brought graduate students with me, and basically the transition, I had two… I had a number of students at the time at Harvard, but several were close to finishing. The youngest one who was closest to finishing was Shelley Anna, who is a professor at Carnegie Mellon University, and she was close enough to the end that she decided to stay a student registered at Harvard. So she completed the degree at Harvard and then did a post-doc; stayed on at Harvard with Howard Stone. But the next student who I’d hired after her was a young guy called Jonathan Rothstein, who started in ’95 or maybe ’96. But he hadn't done qualifying exams at Harvard, and so it was fairly natural for him to say, “I’ll leave Harvard and I’ll move with you to MIT.” So a couple of post-docs moved with me to MIT, Steve Spiegelberg and Gavin Braithwaite. They both moved with me to MIT, and then Jonathan Rothstein as a student. Then I started hiring students at MIT after that.

Zierler:

Mm-hmm [yes], and then it was… So you came into MIT as a tenured associate professor.

McKinley:

Yes.

Zierler:

So the title was the same; the tenure status was different going from Harvard to MIT.

McKinley:

Exactly. MIT has four ranks still at the moment. It has assistant, then associate without tenure, which has the wonderful acronym of AWOT (associate without tenure). Then they have associate with tenure or AWIT, and then they have full professor. So I moved as an AWIT.

Zierler:

And you became full professor in 2001.

McKinley:

That sounds about right. Yeah, somewhere around about there. Yeah.

Zierler:

What is that? I mean obviously the tenure hurdle is completed at that point. What’s the recognition in becoming a full professor?

McKinley:

Yeah. MIT keeps thinking about, and I imagine eventually they will do away with having four ranks because it takes a lot of effort on everybody’s behalf to do reviews. They’re all external reviews, and so you're getting letters from outside. But the feeling was and still is, as of now at least, is that it’s a different rank because it’s much more about service rather than… You’ve demonstrated that you can do research at the level that’s needed to get tenure. You’ve demonstrated that you can teach at a level that’s sufficient for tenure. But it’s now more about service, and that can be service both within the university, chairing committees both within your department and within the university, but also service at a national level on national committees or service in your profession. So that might be, for example, at the time I was editor of a journal, things like that. So it’s looking for that kind of level of recognition that you're kind of a world expert and giving back to the community of scholars broadly.

Zierler:

Mm-hmm [yes]. Now in 2001, this is also the time when the, if I’m saying it right, the Hatsopoulos Microfluids Lab starts? What were the… Is that correct pronunciation?

McKinley:

That is exactly correct, yes.

Zierler:

So what were the circumstances of the creation of this lab?

McKinley:

I think that was partly one of the things that I was hired back to MIT to do, was to help reinvigorate the fluids lab and help raise money to help renovate it. So George Hatsopoulos was a graduate student at MIT. He came from Greece, as you might imagine, from Athens. Came to MIT in the 1950s as a student and stayed. Did a PhD in mechanical engineering at MIT in an area that would be called now thermionic emission. So you would heat… Basically in the early days of the space program when you needed electrical power for a satellite, you had to somehow produce it, and the options at the time were… There were no fuel cells to start with, so the options were either radioisotope generators, and there were lots of concerns, as you might imagine, when rocketry was in its early days of launching things with nuclear cores and polluting things. So they had developed an idea of basically using heat to boil electrons out of a metal. So if you heat certain metals up, they free electrons and you can use those electrons as a power source. So that’s called thermionic emission.

So he started a company as he left called Thermo Electron, and Thermo Electron went on to become a very, very big company in the US. Grew largely by acquisition, buying other small companies, and heavily diversifying because, in fact, thermionic emission never went very far beyond the 1960s in terms of space power because of the development of chemical fuel cells. So that was the end of that, but they grew into a whole bunch of other areas, largely scientific instrumentation. They merged with another company, so Thermo Electron now became Thermo Haake and then eventually Thermofisher, is who they are today, or Thermo Fisher Scientific, now I think they are.

So when he had retired as chairman of the board in late ’90s or [early] 2000s, he wanted to give back to MIT. So we were able to meet with him and talk with him about the future of fluid mechanics and the idea of microstructured materials and microstructured fluids. He’d got a big interest in pumps for blood at the time and he was starting a new company dealing with magnetic impellors for pumping blood, so he was very interested in rheology. So he agreed to use his gift to MIT to kind of endow the lab.

Zierler:

Now how well was the creation of this lab-- How well did that track with the research that you were already doing? Or did you change tracks as a result of the creation of this lab?

McKinley:

No, it fit in reasonably well. Almost all my work up to that point had been polymers only.

Zierler:

Right. Right.

McKinley:

It was at this point that I was starting to get interested in other kinds of materials, so suspensions, magnetorheological fluids, slurries, drilling muds, all sorts of other things. So my area-- And again, I think that’s partly what, when you go up for a review to full professor, that’s the kind of thing that they want to see is that a broad--

Zierler:

They want to see you expanding your interests.

McKinley:

Yes. Yeah. But I think part of it also was that I was able to convince George and the department that that was a good area going forward, and of course the department hired me. So there wasn’t really anyone in the rheology area in mechanical engineering, in our department, and not too many in other [ME] departments across the country, either. So it was kind of a new growth area for mechanical engineering departments as well.

Zierler:

And then yet in 2004 you're sort of back to your home base directing the Program in Polymer Science and Technology, it sounds like.

McKinley:

Yes. Yeah. And that very much is… Because it’s an interdepartmental program, it has a rotating chair, so about every three to five years… You know, it’s natural… Usually the person who’s doing it moves on to do something else, maybe run a department or run something else, and so it goes on to the next person down who is looking for kind of a management experience. Frequently it is someone who is just becoming full professor or wants to become full professor or something like that. So I happily said yes to that because it was a chance to give back to a program that of course had a huge impact on me.

Zierler:

Now how did your directorship of this program influence the kinds of graduate students that you worked with and the ways that you encouraged them in terms of their studies?

McKinley:

Yeah. I tried not to only hire people who would want to work with me, of course. That’s not the goal to do… You know, the goal is not to do that, so I tried very deliberately to make sure that didn't happen. But at the time, polymer science was going through a bit of a change also. I’d say that the days of polymer processing—and a lot of people, when you see polymer science and technology, they think of injection molding and extrusion and fiber spinning and quite traditional things. But in fact the program was not doing hugely well at the time. It was stable, but it wasn’t growing at all because the feeling was that this field was somewhat traditional. It was not an area of growth. There were very few people doing polymer processing at MIT anymore. They’d either retired or left.

So it wasn’t during my time but soon after that that PPST became PPSM as it is now, which is the Program in Polymers and Soft Matter. In the mid-2000s and around 2010 onwards, soft matter became a new term that became increasingly relevant. The difference is that people who are interested in hydrogels and implantable materials, injectable materials, cellular cytoplasm, things like that, they’re all complex fluids. They all contain polymers. They all contain cellular components, but it’s much broader and less traditional. So it became a huge growth area, and PPST changed its name to PPSM. It was always a little redundant to have a program in technology in an institute of technology, so now it’s a program in materials within an institute in technology. So the name makes sense, and it’s really invigorated the program. So the leaders, the people who have led the program in the last decade after me, have done a fantastic job in making it grow.

Zierler:

Now in 2008 you become Associate Head for Research in your department. What does that mean to be associate or the director… What does that mean to be Head for Research?

McKinley:

Yeah. Our department, so mechanical engineering at MIT is the second-biggest department. It’s a very big department, so it has 72 professors. The biggest by far is electrical engineering, but that’s because it’s electrical engineering and computer science, so it’s both. So it’s about twice the size, although… In fact, as we speak right now, it’s actually about to undergo a split because we’re starting a new College of Computing at MIT, so the computer scientists will separate from electrical engineers.

But at the time, it [ME] was the second-biggest department and so it had two seats on what’s called Engineering Council, which is the senate-level management body that reports to the Dean of Engineering. So it’s not by proportional representation really. It’s all the department heads of the nine different engineering departments at MIT. But electrical engineering has three seats on that council because they are so big, and mechanical engineering had two seats on that council. The reason we had two is because we had merged with ocean engineering back in about 2005 or so. Not sure exactly of the date, but the Head of Ocean Engineering had become the first Associate Head of Mechanical Engineering and kept his seat on Engineering Council, as it’s called. So after he had rotated off, we had a new department head, Mary Boyce, who had been at MIT as a graduate student two years ahead of me. She had worked in mechanical engineering in polymers. She hadn't been part of PPST because it hadn't been really in existence when she was starting her graduate degree, but we knew each other very, very well. She was becoming Head and she asked me to become Associate Head.

Zierler:

Now when you were named in your current position as Professor of Teaching Innovation, is this still within the Department of Mechanical Engineering or did you move departments again for this position?

McKinley:

No. The chair… MIT has kind of three different bodies that can give chairs. The Provost level can give chairs, the School of Engineering can give chairs, and then the department can give chairs. So this chair came from the School of Engineering rather than from the department.

Zierler:

Obviously a Professor of Teaching Innovation, part of this is in recognition to your commitment as an educator, so I wonder if you could talk a little bit about is this in recognition of both your undergraduate teaching and graduate teaching, or what would be the recognition there?

McKinley:

Yeah, I guess probably both. At the time I certainly had been involved in reforming our curriculum for undergraduates in fluid mechanics. So we kind of merged fluid mechanics and heat transfer and thermodynamics into an integrated curriculum called thermal fluid sciences, and so that had become a year-long course. So I’d been doing that with two other colleagues, Ernie Cravalho and John Brisson, who had also actually been at Harvard, so he’d been a graduate student at Harvard. The three of us had been tasked with doing that, so that was part of it. Then part of it was graduate teaching as well, so I guess it was teaching on all aspects.

Zierler:

So now I think we’ve reached the point where we’ve covered the sort of narrative milestones. I want to ask you some questions that are going to be introspective and retrospective and can go back as far as you want, depending on the nature of the answer. I wonder if you could talk a little bit about your work developing patents and working with partners in industry. How does that process develop as an academic where you are working in a research environment, but you're working on things that clearly have value out there in the market?

McKinley:

Yeah, that’s a great question and somewhat introspective because I guess I’ve probably never really thought about it. So kind of what strikes me about it is I’ve always been… I’ve never been a pure scientist or a pure engineer. I really like this term engineering science. Engineering science is exactly where I find myself. I like to be in an engineering department. I like to be doing things that are new and original and synthetic, so that part of it very much you follow the scientific process of postulating ideas, checking them out. But I also like to reduce it to practice, to use the language of a patent, so I love to actually have a product, whether it be a widget or an instrument. I like to build hardware and I think I get that from my days with Malcolm Mackley. But I also like to see it finally complete and not just a paper, but maybe something beyond that. So I certainly have colleagues who produce a lot more patents than me, but I also have colleagues who produce no patents and only papers. So for me, the right mixture is somewhere a mixture of both. I like to see new ideas. I like the creation of new ideas, but I also like to see them be useful ideas.

Zierler:

So patents as you see it is really a sign of their usefulness beyond a research or a theoretical basis.

McKinley:

It’s a sign of their potential usefulness, I would say. There are certainly patents I have that… In fact, most of the majority of my patents have never been licensed or practiced, but they potentially are useful, at least. So it may not be commercially viable, but they’re potentially useful at least, I guess I would say.

Zierler:

Do you have any patents that have broken through to become commercially valuable and societally useful?

McKinley:

Yes! Yeah, we have a number that I’d say check one of those boxes, depending on which one. There’s a couple that are licensed through MIT. You know, the growth of nanoscience and nanotechnology in the late 2000s and the 2010s was a great time that Bob Cohen and I were actively collaborating. We had a number of joint graduate students together, and so a lot of that work was funded by the Air Force or by… In fact, actually I had one student who at his [PhD thesis] defense announced that he’d been funded by all three branches of the military! He’d started with Air Force and then he had moved on to US Army, and then he’d ended up with Navy support in the last part of his career.

But all of those programs were very much interested in nanostructured materials or nanostructured coatings that could actually be scaled up, but they weren't just something that you could make in a clean room and do on a 1-cm scale, but that you could actually apply to coatings to prevent, for example, say, oil absorption or oil absorption in soldiers’ uniforms or something like that. So there are a number of nanoscience patents that I had been licensed by small startup companies around the Boston area, and those go through MIT. Then there’s a couple that I had started a company with two former students who both worked for Bob Cohen, in fact, a company called Cambridge Polymer Group. So there are some patents that we have developed together, the three of us, and those broke through, if you like, or were licensed and led to various polymer science projects associated with orthopedic technology, hip implants and things like that.

Zierler:

So what are some of the ethical or legal or financial considerations that you have to be mindful of when you're working on projects that have commercial viability, but you're not working within the context of a for-profit industry? What are some of the things that you have to be mindful of throughout that process?

McKinley:

Yeah. I think the thing that I’ve learned—and you learn it a little bit the hard way, I’d say certainly—is people… Everybody’s expectations change a little bit when suddenly it becomes something that maybe has money associated with it, that there’s potentially a patent. There are people who feel “My name should be on the patent,” or “I should be part of the licensing,” or “I should be on the patent of starting a company.” You learn…and you're never really taught this. You kind of have to learn this by going or by paying attention. You know, the… I’m not sure. The criteria that are required to be a name on a patent are somewhat different than the criteria of someone who would be named on a paper in terms of contributions and whether you had the idea or reduced it to practice. So I think the thing that I learned most importantly is to manage those expectations and make everyone clear of that as early as possible in the process.

Thankfully, I’ve never been involved in any litigation by people claiming, “Oh, I should be a name on that patent,” or something like that, but certainly I’m aware of several cases at MIT like that where graduate students left and then something was patented and they felt they should have been part of that. Trying to explain or unravel who is and who isn't on that is always painful and usually expensive. So thankfully I’ve not had to be directly part of that. The way to do that is to make sure that you manage expectations very early on and say, “This is a creative idea. I think we can reduce this to practice,” but once you have that idea, other people may work on that, whether they be UROPS3 or other students, but they’re not necessarily people who are going to be named on a patent. So you have to be very careful with that because as you said, it’s a for-profit instrument within a nonprofit operation, and so there’s inherently a tension there that you have to be very careful about.

Zierler:

Switching gears a little bit, you’ve spoken very powerfully about the ways that you have benefited from having such wonderful mentors throughout your educational career, and clearly you’ve been an excellent mentee. I wonder, now that the generations have switched, if you can talk a little bit about your style as a mentor and the kinds of things, the kinds of global pieces of advice that you give your students, both undergraduates and graduates.

McKinley:

Yeah. So two very different things. Undergraduates are usually very much focused on “What do I need to do to get my degree? What things do I need to do,” at least to start with. So academic advisees, that’s one thing, and you're trying to steer them through a mass of courses and balancing. Everybody comes to MIT thinking that they’re the very, very best, of course, and you can't bring in 1,000 students every year and have them all be the very best. So there can be sometimes some mismatch and some challenges there. So for undergraduates, at least to start with, it’s that, and then towards the end of their undergraduate time, as their thoughts turn to industry versus grad school, I draw on my own experience. Certainly, I’m very, very thankful for the advice that I had got, so I actually try and encourage most of my students to try and go somewhere other than MIT (or Harvard, back in the day) because I think it’s really important to get a different view of the world.

Zierler:

Kind of like you were saying there’s a Cambridge man, perhaps there’s an MIT man or woman as it were.

McKinley:

There are. There are lifers. No doubt there are ‘lifers’, and of course we want the best. We want to keep the very best, and so the tendency is to try and keep the very best. But I think that it’s great to send someone… My department head at the moment, I taught her as an undergraduate. She was in my undergraduate fluids class in the mid-2000s. Her brother was my PhD advisee, one of my joint PhD advisees with Bob Cohen, in fact. But she went off to Stanford to do her PhD, but now has come back (first) as an assistant professor and now department head. I think going out and seeing the world and coming back is extremely important, so I generally counsel my students to go elsewhere as graduates.

At the graduate level, I guess I try and live and practice advising the same way my advisors practiced it with me, to try and spend a lot of time with students and try and pick the right direction for them without imposing it on them, and maybe do it in a way that… You know, I don't think I realized I was being steered or directed a lot of the time, and I think that’s probably the best kind of mentoring you can do, is lead by example. Give suggestions and gently, but not force people to do things they don't want to do, but try and let them lead themselves in the right direction.

Zierler:

Can you talk a little bit about your involvement with the Society of Rheology, when you became involved? Clearly you're an active member. You believe in its mission. Can you talk a little bit about SOR, your involvement, and why you're so committed to it?

McKinley:

Yeah. I think almost everyone that you’ll talk to in it—and certainly I feel this—feels it is their home. You find that that’s the one scientific community that you're most at home in, and I’m not sure what it is. It’s a very, very supportive community of scholars. It certainly had its turbulent times. I think in the 1950s in particular, there’s all sorts of legendary stories of arguments at meetings and combustible atmospheres and so on, but it has not ever been that way in the time I’ve been involved. Everybody there will give of their time freely because it’s just the right size. It’s not too big that you get lost in, but it’s not so small that you're inbred. It’s got just the right size of graduate students who come and feel supported and senior faculty who have spent their careers there. So it’s a good size. You know, it’s about 1,200 or 1,400 members. Our meetings are typically… They’ve been growing, but they were 300. They’re up to about 600 people. But it’s not like going to an ACS meeting or an APS meeting where there’s 10,000 people and you never see people. You can see everyone and talk to everyone that you want to. You can meet new people, and so because of that, people are willing to do an awful lot for the society. It was the second scientific meeting I ever went to. It was the Santa Fe meeting in 1990 in my fourth year as a grad student. It was the second meeting. I went to an APS meeting before that, the Division of Fluid Dynamics meeting, but it was fantastic. I loved it and kind of fell in love with the society right then.

Zierler:

Now that gets me to my second question. It’s very clear in our talk today that you're very hard to pin down in terms of your expertise and your interest, and you're just involved in so many different areas. I wonder, if I were to try to put you into a corner, what are you fundamentally? Are you a chemical engineer, a mechanical engineer, a rheologist? I mean at the end of the day, if you only had to choose one title that would encapsulate all of your interests and all of your research agendas, what would you be? What’s the best area or title that you would call yourself?

McKinley:

I’ll give you the short answer and then the long answer. So the short answer is indeed I am a rheologist, and the longer answer to this is in a nice thing that was written by a guy called Eugene Bingham, who was our first president. So there’s a really nice history of the first 40 years of the society, and he describes… He came up with the word rheology. He coined the word rheology. He had some classical training, and it’s the science of everything that flows. He announced this at a meeting called the Third Plasticity Symposium in 1928. One of the people who was there was a guy called Herschel, and there’s a model called the Herschel-Bulkley fluid. Once Herschel heard the name, his quotes were something like, “I’ve always wondered what I was. Now I know what I am. I am a rheologist.” So I think that still holds true for me. I always wondered what I was. I’m not really a great chemist or a chemical engineer or a mechanical engineer, but I am a rheologist.

Zierler:

So that’s the easy answer, the short answer, because by definition rheology is interdisciplinary.

McKinley:

Yeah, and I think that’s me. I like to be interdisciplinary, and rheology has swung. The pendulum has swung backwards and forwards. When it started, it really was a lot of people doing plasticity and mechanical engineering, so there used to be a lot of mechanical engineers, applied mathematicians, and even aerodynamics people, so people in aeronautical engineering departments who were interested in plastic deformation of wings and things like that. Then in the ’60s and ’70s, the pendulum swung into it being almost all chemical engineers. But I tell you that pendulum has swung back, and it is now soft matter people and people in material science departments, chemical engineering departments, mechanical engineering departments. There’s no right or wrong department to be part of, and so I love that. I love that interdisciplinary nature of it.

Zierler:

Recently you were inducted as a Fellow of the Royal Society of London, and I wonder if you can talk about what that recognition meant for you both personally and professionally.

McKinley:

Yeah. I think it was the single biggest honor or feeling that I’ve ever had. When you were a student, certainly at Cambridge, you’d see people with their name with the letters FRS at the end of their name, and you didn't even dare aspire to that. They were in this kind of realm that people would whisper, “That’s the person who did such-and-such,” or “That’s the person who invented so-and-so.” So to me, it always was this amazing thing. Ken Walters, who served as an informal mentor to me, was elected a Fellow, and it was just the greatest honor. So that was something you didn't even dare hope might happen, and particularly someone who is not working within the UK or the Commonwealth system. So I think that was personal feeling, and of course made my parents incredibly proud as well to be able to say that. And of course, professionally it’s a validation of all the things that you’ve spent so many years working on and all the work that your students have done with you and so on. So it truly was kind of an incredibly huge honor and you just can't believe it happened.

Zierler:

Now talking about previous inductees that are known for “so-and-so” and “such-and-such,” do you see your induction more as a recognition of the culmination of your achievements, or do you think it was in recognition of one specific project that was representative of all the other things that you’ve been involved in?

McKinley:

I definitely think it would be better to ask other people that. [Chuckles] But I don't think there is one thing that I’ve done that people would say that would be worthy of that, but maybe the combination of all the little things or different things you’ve done. Maybe they add up to make that level of worthiness or whatever. But I don't think I could point to one thing and say, “That’s what did it.”

Zierler:

Well, maybe a better way of asking that question, or at least a way that would make it easier for you to answer, is what do you see as your primary contributions to the field?

McKinley:

Yeah. I’d say it’s, of course, almost all experimental, so almost all of it is experimental work in the field, and probably it’s within the science of making measurements. So it’s developing instruments, developing not just the instrument, but also the analysis that goes with it. So an instrument is only as good as the data you get out, but also what you do with the data. So how do you analyze it? So it’s probably within the science of rheology, people would probably call it rheometry, so making measurements and making good measurements and advancing that. So it’s probably mostly for things in that area, and primarily within the fluid mechanics of stretching or extension, so stickiness and stringiness. That’s probably what most people think of me for.

Zierler:

As an experimentalist, do you see your work as also having theoretical relevance? I mean are theories being improved upon or expanded based on the work that you're involved in?

McKinley:

I certainly hope so, and I think within the rheology…or within the extensional rheology field, I think that our measurements have certainly helped drive forward models for the response of materials, so making models more realistic, thinking about how those models can then be used to solve flow problems or processing problems. So yes, I think the experiments have driven the field forward, but certainly not as much as other colleagues have done in one particular area. So I think it’s a combination of little pushing the envelope forward in a couple of different areas hopefully.

Zierler:

Now given your comfort and excellence in an interdisciplinary environment, I wonder if you can talk about some fundamental principles or laws in science generally—not just physics or not just chemistry, things that you may have learned a long time ago or maybe not so long ago that stay close with you, that sort of inform your approach to any individual area of research that you get involved in, things that are just sort of with you every single day.

McKinley:

Yeah. There is one thing. There is one thing that I find overwhelmingly like that, and it wasn’t something that was taught to me (that I remember being taught, anyway). Maybe it’s something that I’ve picked up and honed and just picked up by osmosis, but find it very useful. It’s this idea of what’s usually called dimensional analysis or dynamical similarity, but the idea under is… Actually, Rayleigh was really the person who really pushed the idea first in the late 1890s and the early 1900s. But the idea that even if you don't know the governing equation, which many times we don't, nature goes by balances of forces, so every term in an equation has the same units or is dimensionally homogeneous, people would say, or homogeneous [changes pronunciation] to use the English expression.

So therefore, even if you don't know all of the things about it, you can use dimensional analysis and scaling to say, “This term is very big. This term is relatively big. This term is very small,” and it gets wrapped up in dimensionless numbers like the Reynolds number or the Mach number or things like that. So almost everyone’s heard of the Reynolds number and everyone’s heard of the Mach number and things like that, so even in the branches of soft matter physics and rheology that we work in, there are the same basic principles that if I’m faced with a new problem, those are usually the things that are my go-to. You know, how big is this? If someone says, in one of my group meetings, “Oh, that term is small,” that’s not good enough. You have to kind of say, “How small? Small compared to what? Can you tell me it’s small compared to another force?” or something like that. So those ideas can get you a hell of a long way very quickly. They never give you the whole answer, but they get you a long way down the right path.

Zierler:

I wonder, in the course of your career—it’s a two-pronged question—are there things that at the beginning of your studies were mysterious that are now not mysterious? You can answer that both in terms of your own knowledge in the field and also the knowledge of the field in general. Are there some things that were mysterious that remain mysterious, insofar as how the field has progressed?

McKinley:

Yeah. Wow, that’s a very big and open-ended question. The things that were mysterious to me, there were many that…you know, the kind of things that people would say and you’d kind of nod and then go, “I don't really understand why he’s saying that or how he’s saying that.” Many of the things when I was at the Newton Institute were like that to me. There were people who were deep, deep into theories of polymer physics. A guy called Sam Edwards was there. Sir Sam Edwards was a professor in Cambridge at the time and was part, was one-half of this thing called the Doi-Edwards theory, and Doi came to visit as part of that as well. So there would be conversations about polymer physics and scaling of this and these terms are important and all these ideas of diffusion over barriers and various other kinds of diffusive processes. They were utter mysteries to me, and so I’d have to go away and sit and try and figure it out and usually get stuck. Then someone like Ron Larson, who was always very kind and would take you aside and explain to you something like that, would point out. So there were many things that were total mysteries to me. I had a good background in fluid mechanics but not in physics, and it kind of emphasized that I never really was that good in theoretical physics. So I had to figure a lot of those things out myself, and I try and… At least when I teach, I will usually focus on those things and say to students, “This made no sense to me as a student, but here’s how I understand it now,” with the hope that that helps them figure it out. Sometimes it does; sometimes it doesn't.

In terms of things that are really still unknown in the field, I think I got really interested in a topic that’s known as fractional calculus at the moment. It’s a way of describing incredibly broad relaxation processes. Many of the materials we deal with have very, very wide range of length scales and timescales, and I just have a feeling that the ideas that have been known for 100 or more than 100 years in this area of fractional calculus can play a role or can be used to describe this. But there’s a huge gap between the ideas, which seem to work really, really well, and a good, firm theoretical underpinning of them. So I wish that connection could get made better, and we’re trying to help work in that direction. But we really need some really good theoretical physicists to get involved.

Zierler:

So I think for my last question, I like to ask questions that are forward-thinking. You’ve already gone sort of in that direction. What things both personally and for your field are you most excited about? What are the things that are possibly on the cusp of a breakthrough, either a theoretical breakthrough or a breakthrough that really improves society? What are those things that continually motivate you to push forward in your field?

McKinley:

Yeah, I’d say within the field, I never thought when I was a graduate student… We’d talk about molecules and we’d describe molecules and then upscale things from molecules to continua. I’d never thought I would see a molecule, and yet the late 1990s, Steve Chu and Ron Larson and people figured out how to fluorescently stain DNA and actually image a single DNA molecule being stretched and deformed. So that’s 20 years old now, but those kinds of tools are still emerging in the biological materials, the ability-- Super-resolution microscopy, things like that, or being able to see single molecules without them being specially just super-long DNA and fluorescently stained, to actually get molecular-level resolution of living cells or living tissues or materials without having to cryofreeze them or stain them or destroy them. So I fully expect that soon we’re going to have nanometer-scale super-resolution imaging of things through some mechanism or another. So all of the instrumentation side of things, whether it be electron-based, neutron-based, x-ray-based—you know, those techniques that used to be very slow and time-consuming are becoming closer to real-time. So I think that’s a super interesting thing from an experimentalist point of view. To be able to observe things on the molecular scale in real-time and measure forces and stresses and so on, I can't wait to see what might happen in that in the next few years. That’s on the fundamental side.

On the commercial side, I guess it’s really then using some of those ideas and making… I fully expect that 3D bioprinted livers made out of rheologically complicated materials, more than one material that can print the tissue seeded with cells, print channels that can be then evacuated or removed for the vascularization—those kinds of things are going to happen, and maybe within the next 10, 20 years. So there’s a lot of rheology in there. There’s a lot more than rheology, of course, in terms of biocompatibility and everything like that, but there’s a heck of a lot of rheology in being able to scan, image, design, build, print, and install, let’s say, a replacement liver.

Zierler:

You sound not only motivated, but you sound excited by these prospects.

McKinley:

I think so. Yes!

Zierler:

Well, Dr. McKinley, it’s been an absolute pleasure talking with you today. Our discussion, I think, is going to be of tremendous value to researchers from so many disciplines. I think that’s only natural, given all of the disciplines you’ve represented in our discussion today. So I’m really grateful for your time, and I’d like to wish you all the best.

McKinley:

Well, thank you very much. Thanks, indeed.

Zierler:

Okay.

 


1: Note for chronology; actually the Falklands War was 1981/82 and I was at Cambridge 82-85; so the time they spent there must have been in air support and peace-keeping roles after the war itself. GHM

2: https://en.wikipedia.org/wiki/Nuffield_Science_Project

3: Undergraduate Research Opportunities Program Students (UROPS)