Thomas H. Epps, III

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ORAL HISTORIES
Portrait of Thomas Epps

Credit: Kathy F. Atkinson, University of Delaware

Interviewed by
David Zierler
Interview date
Location
video conference
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Interview of Thomas Epps, III, by David Zierler on July 28, 2020,Niels Bohr Library & Archives, American Institute of Physics,College Park, MD USA,www.aip.org/history-programs/niels-bohr-library/oral-histories/XXXX

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In this interview, David Zierler, Oral Historian for AIP, interviews Thomas H. Epps, III, the Thomas and Kipp Gutshall Professor of Chemical and Biomolecular Engineering at the University of Delaware. Epps describes his involvement and leadership in several research ventures in materials at Delaware and some of the challenges regarding lab work during the coronavirus pandemic. He recounts his childhood in Virginia and the influence of his parents, both of whom were university professors, and he discusses his early interests in math and sciences in high school which culminated in a formative project at NASA Langley. Epps describes his undergraduate research at MIT where he pursued a degree in chemical engineering and where he solidified his multidisciplinary approach to the field. He explains his decision to attend the University of Minnesota for graduate school, where he worked under the direction of Frank Bates on polymers and nanostructure membranes. Epps describes his choice not to enter industry after graduate school, and he explains his decision to conduct postdoctoral work with Mike Fasolka on polymer-thin films at NIST. He explains the circumstances leading to him joining the faculty at Delaware, and he describes his excitement at the prospect of serving on and creating many research endeavors across the university. Epps discusses his broad interests in biotechnology and fuel cells, and he describes Delaware’s leadership role in its partnership with the Department of Energy in pursuing sustainable energy sources. He describes what chemical engineers can contribute to Covid-19 research, and he reflects on the ways STEM has, and has not, become more inclusive and diverse over the course of his career. At the end of the interview, Epps describes the ranges of research endeavors in the material sciences that excite him most as he looks to the future.

Transcript

Zierler:

Okay. This is David Zierler, oral historian for the American Institute of Physics. It is July 28th, 2020. It is my great pleasure to be here with Professor Thomas H. Epps, III. Thomas, thank you so much for joining me this morning.

Epps:

Thank you very much for having me, I am honored to talk with you.

Zierler:

All right, so to get started, would you tell me your title and institutional affiliation?

Epps:

I am the Thomas & Kipp Gutshall Professor of Chemical & Biomolecular Engineering. I have a joint appointment in Materials Science & Engineering, and affiliated appointment in Biomedical Engineering; all at the University of Delaware. I am also the director of the Center for Research in Soft matter and Polymers, as well as the director for our new MRSEC (Materials Research Science and Engineering Center) funded by the NSF, called UD CHARM. And I am the deputy director of our new EFRC from the Department of Energy, an Energy Frontier Research Center, named CPI, which is the Center for Plastics Innovation.

Zierler:

So you really don't have much going at all these days, I guess, right?

Epps:

Enough to definitely keep me busy, but we have a great group of colleagues, and they are very collaborative, which allow us to get a lot of things done.

Zierler:

And it's very clear that University of Delaware is one of the most exciting places in the world doing this materials science right now.

Epps:

It definitely is. We've got everything from biomaterials, drug delivery, gene therapy, to composite materials. We have a center associated with the Army on composite materials. Life-cycle management, sustainability, plastics innovation, materials from biomass, fuel cells, and batteries, all sorts of various things related to materials science, soft materials, and hard materials.

Zierler:

Now, in terms of your work style, are you a multitasker? Are you doing like seven things at once for all of your different research projects and affiliations? Or do you tend to sort of block out particular periods of time or particular days to work on discreet projects?

Epps:

I think I do some of both. One of the nice things with the different projects, is that there are some synergies, and the synergies allow me to do some multitasking. And many of us are involved in multiple centers. However, I find that for me it's sometimes nice to just sit down and block out, not maybe a day, but definitely a couple hours on the calendar to devote to various activities, just so that I can really focus in on the details.

Zierler:

Now, in terms of the lab work that has an obvious physicality to it, how are you coping these days with remote work in the pandemic?

Epps:

Well, it's been a little bit interesting. Personally, I don't get in the lab very much, which is unfortunate, because I really like to be able to get in the lab and do the experiments and show my students and postdocs and undergrads that I still know how to do it. I don't quite get to do that as often as I'd like. However, we're able to cope, and we've done that in a couple ways. One of the nice things is that the group is fairly collaborative, so it's easy, or I wouldn't say it's easy, but it's feasible to necessarily hand off different topics so that we can schedule and coordinate. And because the group really gets along, it makes it very straightforward to do that. One of the things that we have done and one of the nice aspects about the group, is that we're really versed in understanding fundamentals of structure-property relationships, and how we might apply that to applications, but at heart, we really want to understand the fundamentals, and so the unfortunate situation with the pandemic has really given us the opportunity to go back and do some theory and hone some modeling routines that hopefully we'll be publishing shortly. Many things that we hadn't necessarily thought about doing a year ago, but ideas that have really helped us focus in on the next set of experiments that we're doing now, and hopefully we'll do in even more frequency as the situation improves.

Zierler:

Now, you mentioned something that jumped out at me. This is an opportunity to focus on theory. Is that to suggest that you sort of have a fluid approach to, you know, your expertise in theory and in experimentation? Or are you talking about relying on colleagues who are sort of more theorists properly, and this is an opportunity for collaboration with them?

Epps:

Some of both. One of the things that we want to do, even as an experimental group, is that we don't want to just understand the experiment and purely report empirical results. It would be nice to take our results and connect them, if we can, to some fundamental theory. That allows us to improve the translatability of our results. Yet, in the cases where we have theoretical or computational collaborators, I'm not saying we can do their jobs, because we certainly cannot, but we really try to understand as much as we can about what our collaborators are doing so that we can design our experiments, to really complement the collaboration. So, it's not so much reinventing ourselves as it is applying our knowledge to try to make some small dent, I guess, in computational and theoretical development where we can.

Zierler:

All right, Thomas, let's take it all the way back to the beginning. Let's start with your origins, and let's go first with your parents. Tell me a little bit about your parents and where they're from.

Epps:

So, I'm going to digress for just a second, which is probably dangerous during this kind of thing. But I was really excited a couple days ago because I found out that I now have a Wikipedia page.

Zierler:

Oh, wow.

Epps:

And that some very nice folks set it up for me, and I didn't know about it until I got a tweet about it earlier this week.

Zierler:

Did you learn things about yourself that you didn't know? (laughs)

Epps:

Well no, not necessarily that, but the reason that your question made me bring it up is because it actually does very nicely start with my parents.

Zierler:

Okay.

Epps:

And so, my parents were extremely, and still are, thankfully they're both still alive, so both extremely important to the things that I've done and still important to what I do today. I was very lucky in the sense that both my parents were professors. They're retired now. My father in chemistry at Virginia State University, and my mother in accounting starting at Virginia Union University, and then moving to Virginia Commonwealth University. So naturally, then, I became a chemical engineer, so that I could do the math and the chemistry associated with my parents.

Zierler:

And where did your parents meet?

Epps:

They met in Virginia in the Richmond, Virginia area. They both grew up there and that's where I grew up, just outside of Richmond, and went to school in that area as well.

Zierler:

And did you go to public schools throughout childhood?

Epps:

I did. And for me, that was a wonderful experience that I think still helps me to this day. I was lucky in the sense that, yes, I went to public school, and I lived just outside of Richmond in an area where we had a mix of the city, the suburbs, and then also at that time, a bit of the more country environment as well. I played baseball growing up, but in high school, I really had the opportunity to focus on teamwork, working with people from different backgrounds, coming together, and doing things as a group. I think that has really helped me in terms of how we run our research program, valuing input from everyone from a diverse background. A lot of our collaborations focus on experiment, theory, computation, how can we bring those things all together and learn from each other? And that comes from my being in public school and being with people from all different backgrounds, working with different types of people, and just kind of understanding where everyone's coming from.

Zierler:

Now, you emphasize diversity. Was your neighborhood growing up, was your school, was it a pretty diverse place?

Epps:

I would say it was definitely-- you're testing my memory a little bit-- but it was reasonably diverse in the sense that we were basically on the border of the city, all the way out into the country. We were fortunate enough to live in a relatively nice suburban community, so we definitely had some diversity. Mirrors probably a little bit of the statistics of America, I would say, in terms of the diversity, but I was fortunate to be able to interact with all different types of people.

Zierler:

Thomas, when did you realize that you had a special aptitude in math and science? Was that sort of even before your formal exposure in middle school and high school?

Epps:

You know, that's an interesting question. I would say that I've always been comfortable with math and science. I've always liked doing science experiments. I used to, as a young kid, have the "opportunity" to go to work with my dad, if I hadn't found a job or anything else to do. The nice part about that was really getting to play with the chemistry models in his office and sitting in on some of the classes. Not claiming I understood everything that was going on, or even most of what was going on at the time, but just really getting to see his love of chemistry. The same thing with my mom. And one of the things that was nice about our school is that we were lucky in the sense that they had opportunities for enrichment. I had the opportunity when, I believe, I was a junior in high school to participate in a Virginia Governor School Program. That was my first hands-on introduction to polymers, what we do now, and I worked at NASA Langley with a gentleman, Dr. Philip Young, and we worked on designing an atmospheric simulator, which basically simulated the space environment, atomic oxygen content and UV radiation exposure, looked at a series of polymer films, and compared them to materials that flew on the remote manipulator arm of the space shuttle. As a high school student, it was a really cool experience.

Zierler:

Were you a stand-out student in math and science in high school?

Epps:

I would say I held my own. One of the nice things, again, was that there were a bunch of other great students at my school, so, I definitely did well, and there were others that did well that I had the opportunity to interact with, such as work on the physics problem sets and the chemistry homework and those sorts of things together. I wouldn't necessarily say "stand-out" but I definitely was able to hold my own.

Zierler:

When you were thinking about schools, did you think specifically chemical engineering as early as high school, or that would come later on in college?

Epps:

I definitely thought about it in high school. And part of that was just being fortunate to have the opportunity to be around chemistry growing up, and my next-door neighbor worked at DuPont and then ICI. Just being able to see some of the advances that were happening when you could take some of the chemistry, transform it, and move it into the marketplace. I was lucky enough to see the DuPont Spruance plant and look at how KevlarTM was produced and that was quite fascinating. Or Allied Signal, which was doing some carpeting and many other things. Being able to see how you could take chemistry, scale it up, and produce products, was something that excited me, and I still liked the math, and so for me, chemical engineering was a nice fit.

Zierler:

Now, growing up, how well did you understand what the professor's life meant from your parents? Was this something that you said, "I see what they're doing and they love it, and this is something I want to do"? Or did you sort of go in the other direction and think you would end up in industry?

Epps:

I would say that I kept my options open. Definitely through undergrad. My undergraduate advisor, I went to MIT for undergrad, tried to talk me into going to the University of Minnesota for grad school. I guess he did a good job, since that's where I ended up. That opportunity really showed me what I wanted to do in terms of moving into academia, interacting with students, watching people grow. But then, also, having the opportunity to pursue some of my own research activities and propose research questions. That's one of the things that I really enjoy, being able to think about the scientific questions and convince people that I should be the one to help solve them. Whether that is convincing them in terms of giving me some grant money or convincing a student or two or three to work with me on that project. But then really having the freedom to choose our own adventure to some extent, and hopefully come up with a pretty unique and translatable and long-lasting solution.

Zierler:

What schools did you apply to besides MIT?

Epps:

Let's see, I applied to the University of Virginia. A very good school, also not too far from where I used to live. And so that was definitely a bonus. I also applied-- the one other place I remember-- was University of Michigan. I didn't apply to too many schools. That was still back in the day where you had to type things out, and it sort of limited the number of applications, not quite like on the computer today, where it seems, at least in my view, to be a little bit easier to apply. I know there are still the application fees, but I definitely tried to limit the number of applications.

Zierler:

And why did MIT win out?

Epps:

Its reputation. I mean, just being a very good school. And I was also lucky because I played baseball, I had the opportunity to go up and visit very early in the spring. I don't remember exactly when it was, but I think I remember that the Charles River was pretty much frozen over, or if not, at least that's my memory of it. I had the opportunity to walk around campus, talk to some different faculty and students, talk with the baseball coaches. So, I ended up playing baseball at MIT. And it just felt like it was a very nice fit for me.

Zierler:

What's the name of the MIT baseball team?

Epps:

We're the Engineers. Our mascot is a beaver. We do our best work at night, is the joke, and I don't have mine with me right now, but almost everyone... has a brass rat, which is a ring that has the beaver on it, a picture of the campus skyline, and other features. But we're the Engineers, or Beavers, depending on who you talk to.

Zierler:

Now, because chemical engineering is inherently multidisciplinary, I'm curious about the curriculum and the kind of courses that you were expected to take, and the kinds of electives that you wanted to take as your own scholarly interests grew over the course of your undergraduate career?

Epps:

I think that's one of the really nice things about chemical engineering, is understanding the multidisciplinary and flexible nature of the program. Even what has happened in traditional departments -- I gave you the mouthful of the names of centers and things that I'm associated with but -- one of the things that I would point out is that when I started at the University of Delaware, we were the chemical engineering department, now we're chemical and biomolecular engineering. We were embracing some of that breadth and depth as it goes to the biomolecular focus. Now, back to the classes though, one of the nice things, even during my time at MIT, is that you have a lot of opportunity to take classes. Obviously, you have to take core classes in your core competencies and courses like thermodynamics, kinetics, fluids, and heat and mass transfer. But outside of that, you have the opportunity to focus on biochemistry or catalysis, or computation. There were a lot of electives in polymer science. MIT had a polymer science program that graduate students-- I was an undergrad, but the graduate students could participate in. They also had a Practice School program, which was a really-- which, still is, a really unique experience, where you have the opportunity to take some graduate coursework but then instead of doing, say, a M.S. thesis, you go do an internship at two different companies and use those write-ups and reports in lieu of your thesis. One can think of it more as going out as an MIT consultant working at a company; whether it's working on polymers and plastics, or working on new bioreactors for a pharmaceutical company. You can even imagine a team going out and working with vaccine development. Those things are obviously relevant to today's climate.

Zierler:

Did you get the sense that in the department, that students or even professors, would at the end of the day pick a team that they played for where it was like, "Well, I'm really a chemist who does chemical engineering," or, "I'm really physicist who does chemical engineering," or a biologist. Did you see it in those terms, or was it really just a matter of chemical engineering is the basis for professional identity, and then you reverse-engineered the major field that you work in?

Epps:

I guess it would be more of the second in some senses. One of the nice things about being in chemical engineering is, as long as you have those core competencies, then you can bring whatever additional skills you have to the table, and so in some cases you might find that might be chemistry; and that's designing and synthesizing new molecules. In some cases that might be coding and really optimizing a program so it runs more efficiently so that I can use less nodes and less processor time. It might be understanding transition states and exploring catalysis, or even so much as getting to materials science where it may focus on how to better utilize a TEM in order to probe and understand atomic bonding on gold surfaces and those sorts of things. And obviously, we can't forget about the biological aspects, whether that is thinking about protein engineering, whether that is thinking about metabolic pathways and metabolic design – such as how do I get my cells to do what I want them to do? And you might think, well, what's the chemical engineering in that? But if I start thinking about cellular processes, and I can think about that cell as a very complex reactor. I've got a series of kinetic equations that can hopefully describe that process. I can think about transition states and balances and reaction pathways. And so, there's a lot that fundamental understanding in a biology or chemistry or physics or environmental engineering that can play a role in really helping you become a better chemical engineer. I laugh about some of the collaborations that we have in my group, we've had cases where I have one of my favorite chemists that we work with, where we make some molecules, some polymers for her, and she does the electron microscopy. That's one of our projects, and she's the chemist. Then the other project is, she makes some cool molecules for us and we put them down on surfaces. So, it's really just taking advantage of your skill sets and finding the right people to complete a good team.

Zierler:

Now, in terms of establishing those core competencies that you refer to and then branching out from there, what are, you know, based on your overall expertise in the field and education, from the vantage point of chemical engineering, what do you see as those core competencies?

Epps:

For me or for the field?

Zierler:

Both.

Epps:

Let me start with myself. One of the nice things, especially in my graduate education at Minnesota, was that it's a combined chemical engineering and materials science department, and so that really allowed me to get a firm foundation in chemical engineering, and in materials science. Now, there are some separate aspects of the program, so I took the chemical engineering courses, as opposed to the materials science courses, but once we got in the research groups, I was able to focus on understanding structure-property and structure-property-processing relationships. Basically, what does the material look like on the nanoscale? How does that nanoscale structure influence material properties? its thermal properties? does it crystallize or melt? does it flow or not flow? And then thinking about how do you use that for different applications? So, if it flows at room temperature, is that a good material for a tape? Is that a good material for a battery membrane? Is that a good material for a lubricant? How can we tune those sorts of properties? In terms of where we take that now, one of my favorite subjects in chemical engineering is thermodynamics, and that's one of the things that we bring to the table in terms of really understanding phase separation, phase mixing. How chemical constituents impact that thermodynamic process. For instance, at what temperature does something melt, freeze, or boil? How much sugar can I add to the water before it falls out of solution? How does that change with temperature? All of these are core competencies. In terms of chemical engineering, I would say that in general, we hope that our students come out with a good understanding of the thermodynamics, and also kinetics, reaction equilibria, but then also are able to think about optimization. One of the things that I think that all of us in chemical engineering really take pride in, is that our students can come out, see a problem, really distill it down into the things that they know, and then go about solving it. And what I mean by that, is taking something complex, breaking it down into the key components that we can understand, finding out what we don't understand, and knowing where we can go to get advice to help solve that problem. From the chemical engineering standpoint, it's great because that's why you see chemical engineers not just in chemical plants, but also in investment banking, law, and other places, because it's really the ability to take your core competencies, distill everything down, and then solve a challenging problem just by framing the situation.

Zierler:

In what ways did MIT encourage, either through the relationships you built with your professors, or just the way the curriculum was set up, in what ways did it encourage you to branch out from those core competencies and discover your own talents and interests?

Epps:

One of the key ways was through their UROP program, U-R-O-P. I believe it's Undergraduate Research Opportunities Program. One of the things that the program really allowed me to do was pursue opportunities for semester and summer research. I had the wonderful fortune of working with Professor Paula Hammond when she was getting started at MIT. She's now, as you may know, the department head there and has done so many wonderful things, and it's always great to see. And by the way, I should mention that no matter what she's done, she always has a smile on her face. That's extremely inspiring to see that in the midst of the enormity of the activities in which she's involved. But I had the opportunity to really work in her lab, and I can say the smile is genuine, and she really cares about all of the students. I worked on a side-chain liquid crystalline project. I had the opportunity to get in the lab when it was first getting started, be a little on my own in the sense of having the opportunity to explore, learn about different synthesis techniques etc. I also had the opportunity to gain some knowledge from other labs, such as Tim Swager's lab over in the chemistry department, we needed to learn about a particular device. The undergrad research program really allowed me to explore and find subsets of engineering and science that were of interest. One of the other things was that I had the opportunity to participate in a startup venture. In that particular case, it was as part of the MIT $50k competition, and that was a great experience in terms of working with a team on a startup idea. Being able to take that idea to a competition and actually, we didn't win the $50k, but we were able to win a nice honorable mention that came with some legal advice and other things associated with the company. That was another fun activity. One of the other things that was really instrumental, to me, was MIT's concentration program, as it was called, where you take your core courses, but then you choose courses that are in some area that's outside of your major field. In this particular case, I chose anthropology. The first class that I took was Magic, Witchcraft, and the Spirit World. It was an interesting class. It was a lot of fun, and then what ended up happening is that I took some classes on Mayan and Aztec studies. And I really enjoyed that aspect of learning about the intersection between anthropology and archaeology, learning about architecture, and it's even led to things where... my wife and I have hiked Hadrian's Wall, stopping at the different mile forts. This dovetails with our love for outdoor activities etc.

Zierler:

Was there a culture of entrepreneurialism at MIT? Particularly because chemical engineering, obviously, is so relevant to industry. Were students encouraged to explore some of the commercial relevance of their research, or this was something more that you did on your own?

Epps:

Well I would say a combination of both. I would say that you were definitely not required, but it was all around you. It's one of those things where I wouldn't say it was encouraged or discouraged, but it was hard not to see it, and it was hard not to get excited about it.

Zierler:

And I wonder if also that's a comment on Cambridge and Boston generally? Tech and startups and all of that.

Epps:

I think it is. I think it's also a location that's growing around Cambridge, right on the Charles River. I believe that Novartis has now built a facility there, and I think Genzyme and a few other companies, hopefully I'm not getting those names wrong, are also up there as well. I was fortunate enough to be a Martin Luther King, Jr. Fellow and did my sabbatical in the chemistry department in 2012-2013, so I was really able to see some of the growth. But there's definitely a lot of opportunity in the startup space. I've sent graduate students from my group up to the Boston area to participate in startups. And even undergrads as well. I’ve had undergrads from Delaware that went to MIT and are now involved in some relatively successful startups.

Zierler:

Now you stayed on for your masters degree at MIT. Was the original plan to continue that through the PhD, or did you see the masters as its own terminal program?

Epps:

Thanks for that question, it gives me a chance to clarify. The Practice School program for undergrads was an opportunity to continue on to masters, with the understanding that we would either go into industry, whether that was startup etc., or go to grad school elsewhere. It was not a route to PhD at MIT [for MIT undergraduates]. One of the things about the program is that it has evolved, and it also provides a nice opportunity for incoming PhDs from other places to also get involved in that Practice School program as part of their PhD experience. It's a nice dovetailing of undergraduates that are moving on to do other things that get to participate and then PhD students that are coming in and starting fresh that also get to mesh together in that same program and then keep going in their own directions.

Zierler:

And in terms of graduate schools, was it particular professors that you wanted to work with? Was it the reputation of programs in chemical engineering? What were your main objectives and decisions when you were thinking about graduate school?

Epps:

There were a few things. Again, I think that all the experiences that you have in life can help inform what you do next. In my particular case, I was a GEM (Graduate Education for Minorities) Fellow, which supported part of my Masters work. One of the things that I did as a GEM fellow is I took an internship. I worked at Goodyear Tire and Rubber Company in Akron, Ohio with a gentleman named Dr. Adel Halasa. He was one of the key contributors to the Aquatred tires. But as part of that experience, I talked to him a lot -- he was a great mentor. And we would sit down -- and he would always -- he loved to chew on ginger; ginger root; raw. We would chat and he would say, you know, "Thomas, we should talk about grad school and where you're going to go, and what you're going to do." And we would talk, and then one day I was in the lab and he said, "C'mere, c'mere, c'mere." So I went. And he said, "I want to introduce you to somebody." He introduced me to Prof. Frank Bates, at Minnesota. And he told me, he said, "You should work for him."--

Zierler:

What was Frank doing there?

Epps:

I don't know. At that time, I think I was a--

Zierler:

Maybe he was there to meet you.

Epps:

--a senior undergrad, so I doubt he was there to meet me. But it was just a great opportunity for me to meet him, but it kept University of Minnesota on my radar. I'm from the East Coast, went to school on the East Coast. As you can see, I still like it. I'm back on the East Coast. So, I hadn't really--

Zierler:

If Boston wasn't cold enough for a guy from Virginia, you wanted to check out Minnesota, right?

Epps:

(laughs) Well, it's interesting that you mention that. I found, and most people will think this is odd to some extent, but I found Minnesota a bit more manageable than Boston because I don't mind cold. We [my wife and I] do a lot of outdoor mountaineering. We've climbed Mount Rainier. My wife and I climb Mount Washington in the winter. So, when it's below zero, that's fun for us.

Zierler:

Wow.

Epps:

But cold and wet is what you get in Boston, and I would rather be cold and dry than cold and wet. Now, there was one day in Minnesota walking to school where my eyelashes, a couple eyelashes, broke off when my eyes froze shut. But that's a special circumstance. But in terms of even thinking about Minnesota, one of the things that really attracted me was, the opportunity to work with Frank, which is what I ended up doing, but more importantly the opportunity to have a series of potential advisors that I could choose from in my area of interest, which at that point had narrowed down to polymers. The opportunity to work with, and not meaning to leave anyone out, but people like Tim Lodge, or Marc Hillmyer, or Chris Macosko, Matt Tirrell, and Dave Morse. So, there were a nice group of people that did polymer work-- or Dan Frisbie-- who was doing some collaborative work in polymers and electronic materials. So, it was more than one person, but that opportunity to be something, to be part of the polymer group experience. That was quite nice. There were also some other folks like Frank Snowden, who unfortunately passed away several years ago, but he was very instrumental in recruiting students, especially under-represented minority students, to Minnesota, and trying to help make people feel welcome.

Zierler:

Now, by the time you got to graduate school, was polymers sort of central to your research focus and what you wanted to work on?

Epps:

Well, let's put it this way. If you're in high school and you get to have a polymers project where your materials fly on the space shuttle, you're sold. So yes, from the time I got to undergrad, I had really narrowed my focus down to polymers. And there was nothing in, for example, Paula Hammond's group that swayed me from continuing along that route. In fact, I would say that’s where the focus was fine-tuned to focusing on polymeric nanostructured materials. That was focused through Paula's group, where we were looking at side-chain, liquid-crystalline polymers, polymers that you would use in calculator displays, radar displays, and other things. My time at Goodyear where nanostructure materials are what give tires the properties that you want, that tackiness, but then also that ability to withstand a bump without basically shattering or falling apart. But then also providing that impact and shock absorption so that you don't feel like the Flintstones going down a road on a solid rock-based tire. Learning about nanostructure really got me excited about continuing to pursue that particular avenue.

Zierler:

What was the distinction or the ratio between coursework and lab work at Minnesota? Were you in the labs mostly? Was there a core course requirement before you would focus on your own lab work?

Epps:

Yes, there was a core course requirement, and in this sense, again, I was a little bit fortunate from the standpoint of having completed the MIT Practice School program. As part of that program, I took some grad courses, and Minnesota was nice enough to acknowledge some of those courses. So, I was fortunate to be able to get in the lab maybe a little bit sooner. But there were definitely course requirements in thermodynamics, fluids, some advanced math courses that students had to take, and then I had the opportunity to take a statistical mechanics course and some others, like polymer science courses. So some of the courses that I took for enrichment purposes were in statistical mechanics and X-ray crystallography. Polymer physics also was another great course.

Zierler:

What was the process for you in terms of developing your dissertation?

Epps:

I started on... Frank convinced me that we had this great project on fuel cell membranes that we were going to design using block copolymers. And it sounded really exciting. We went in the lab to get started. My thesis, I believe, does not mention the word fuel cells anywhere in it, which ended up being fine because it was an opportunity to go in, try a few things, and then shift towards polymers for battery applications. Not wildly different, because it was still in nanostructured membranes, but shifting our focus a bit. One of the nice things about being in Frank Bates' group was the opportunity to craft my own project and pitch some ideas to him. He was great in the sense that he obviously had things that he wanted you to do, but I had that free time and flexibility to satisfy my own curiosity. I could go in, try some experiments, and tell him, "Hey look, can we maybe not meet for two weeks because I'm working on something? I think it's going to work but I need some data to convince you," sort of thing. There was that opportunity to be able to do that, and then he was great about, okay, let's sit down and be honest and say, "Is this working, is it not working? Is this path working for us in terms of the idea and the experiment, is it not?” It allowed me to be efficient in the things that we were pursuing, which was something that, to this day, helps me in terms of, what can we do that's going to have an impact, how to pursue it, when to continue, when to cut things off. For me, it was a very nice experience in terms of the dissertation process; and I was able to work with some other great graduate students, so having some joint papers, playing some racquetball and cribbage, etc. To be in a nice group, where we had the opportunity to do some really good science, but then also respect each other and have some time outside of the lab too.

Zierler:

The process of doing a dissertation really helps clarify exactly the kind of field that you're working in, as you become more and more focused on a particular project. So, to come back to this theme of the multidisciplinary nature of chemical engineering, what did you see as one or more of the subfields that were most relevant and where you saw your research questions having greatest applicability?

Epps:

Where my research questions had the greatest applicability would be thermodynamics. We were focused on was two aspects of a problem. One was, when we have block copolymers, so two polymers [chemically connected]. Think polystyrene, which is something that you might find in styrofoam cups, and polyisoprene, which is something that constitutes natural rubber, but you can think of the consistency of polyisoprene as being like cold molasses. If you take those two polymers, and chemically connect them together, they are not identical so they want to phase separate. But you've chemically connected them together, so they phase separate on the nanoscale. One of the things that we wanted to do with our polymers, which were similar to polystyrene-polyisoprene, is understand how does that phase separation occur? Really understanding the thermodynamics of a polymer chain? Does that drive phase separation? What is the relative chain length? If we think of those chains as red and blue, is that blue chain longer than the red? Is the red chain longer than the blue? That influences the phase separation, the time scales, etc. If you think about that making phase diagrams, that's very much based on thermodynamics. But then the second aspect of that was, if we want to make a membrane, we have to add a conducting material. In this case, we added a lithium salt because we want to make lithium ion battery membranes. When we add that lithium salt, where does it go? It goes into the nanostructure somewhere, and the questions are: does it go into one phase, does it go into the other? does it go into both? what are the relative fractions in each phase? how does that influence its ability to move? how does that influence transport?

There were a lot of fundamental questions that we could answer, and then it didn't necessarily just apply to a lithium battery membrane. It also applied to a fuel cell membrane, or an actuator, or a robotic arm. All those things where I need to think about adding a salt or another additive. How does it conduct through a polymeric material? So really understanding that thermodynamics and phase behavior is crucial, and we had some really nice answers to some of the key questions, but one of the next things is that it's a growing field, and so we even address some new areas where there are some open questions that we can continue to solve today.

Zierler:

When you finished your dissertation, did you think at all about entering industry? Did you have any offers to pursue things beyond the academy? Or were you sort of laser-focused on a traditional academic track?

Epps:

20-30 years ago, there was a lot more focus in chemical engineering on hiring graduate students [for faculty positions]. Essentially, getting your faculty offer before you finished your dissertation, finishing your dissertation, and then starting your faculty position. I was lucky enough, or old enough, I guess, at this point, to be one of those people in that particular position. During my last year of graduate school, I interviewed for faculty positions and was able to secure one. And then I went off and did a postdoc for a year and a half, and Delaware waited until I showed up. I will just point out somewhat tongue-in-cheek, that they hired myself and another person [that year], Millie Sullivan, who has been a great collaborator and really successful. She was also hired as a graduate student and up until this past year, that was the last time that Delaware [Chemical Engineering] had hired graduate students without starting their postdoc first. So, we almost wonder whether we did something wrong for that to happen. Anyhow-- I guess that's where the situation is a bit different in the sense that I was lucky enough to get a faculty position before I finished my thesis, so there was a little bit less angst about, "What am I going to do next?".

Zierler:

Yeah. How did the NIST postdoc come about for you?

Epps:

So that came about, as a result of a call for National Research Council Postdoctoral Fellows, and I wanted to go back to the east coast. At that time, I knew I was going to be in Delaware two years later, and so I was looking for appropriate opportunities. Tim Lodge, who had been on my thesis committee, had done his postdoc at NIST, and so just looking at various people that had done their postdocs there and been successful, I decided that it would be a good opportunity. I was able to connect with a gentleman, Mike Fasolka, on a potential project, which was focused on taking nanostructured polymers and trying to understand thin film processing aspects. What happens to that phase diagram when I process it? What happens when I make it into a coating? It was a really neat opportunity to work in the National Lab, do some basic science, but then also interact with a group of other postdocs and scientists that were really interested in -- how do we measure things? How do we understand behavior? How do we link that to commerce? NIST is in the Department of Commerce, and so really understanding weights and measures and standards is very important in the mission.

Zierler:

Was NIST a really good place to do a postdoc in terms of helping to form your professional research identity?

Epps:

Yes. I would say in a couple different aspects. The first aspect is definitely research-wise. Moving into polymer-thin films is something that was very beneficial to my research. It's one area that even to this day, we still do a lot of work in understanding polymer thin film behavior. [asking questions like] how to manipulate that behavior? As a matter of fact, we were working on a patent related to that topic yesterday afternoon with one of my postdocs. It's something that's been instrumental to our core research. And some of my highest-cited papers are related to polymer nanostructures and thin films. So that's been great. The other aspect that is-- I can't really rank relative importance, but equally as important I'll say--, is the connections that I made and the people that I met then, who I still work with today, whether it's doing neutron scattering at the neutron source at NIST; whether it's advisory board for one of our new polymer or plastics innovation centers, or our MRSEC. In our centers, we have people that are advising us who are people that I met during my postdoc, and so the professional development and community building opportunities that you can get at NIST were equally as attractive as some of the research opportunities.

Zierler:

Was there at NIST a basic research environment, or were you expected to sort of slot into an existing project and just contribute to what was going on before you got there?

Epps:

Some of both, which was great. In my case, I was able to craft my own research project, which with Mike Fasolka, I was able to pursue. But then I was also able to participate in the NIST Combinatorial Methods Center, which was an industrial consortium that was focused on how do we streamline the process of analyzing and understanding polymer films and systems. It was an opportunity to work on some side projects that were already started that were beneficial to industry, and allowed me maybe to make a few connections to understand how my research could fit into an applications base. That was a nice thing, perform the basic research, and then be able to see some of the more applied aspects as well.

Zierler:

Now, because you were all set with Delaware even beforehand, and because of the proximity, it's not too far from NIST, I'm curious if you had any sort of preparatory contact with them, if you wanted to hit the ground running when you got there, or you really just started fresh on day one when you arrived at Delaware?

Epps:

I did some of both. One of the great things about UD was the opportunity to order equipment in advance so things showed up quickly... when I was there, a lot of my equipment was there, so I didn't have to spend the first six months waiting for things to show up. My lab was ready to go. One of my colleagues, Norm Wagner called me and he said, "Thomas," he said, "I know you're not starting yet, but I'm teaching sophomore thermodynamics. Send me a description of two projects that you'd like to offer to undergrads. I'm going to advertise them in my class." And so, he did, and I got Paul Brigandi and Tom Scherr, and they were the first two members of my group. Two undergrads started with me in the lab. [They] helped set up equipment, set up the lab, and set up our flow-coating instruments that we use for our thin film studies. It really helped me hit the ground running, and it's something I probably would not have thought of other than Norm calling and saying, "Hey, I'm going to do this. Let's get started." I would say that was great. The other thing that was nice is I had the opportunity at NIST, and Mike Fasolka provided me with this, a little bit of time to work on things that I was going to continue at Delaware. I even had the opportunity to work on my NSF CAREER proposal during my time at NIST so that when I started at Delaware, I could submit that on day one.

Zierler:

Now, as you were preparing to become a professor, I'm curious what were some things that you learned from Frank Bates, in terms of being a mentor and a teacher, as you were envisioning quickly taking on your own graduate students and leading labs and providing the kinds of advice in the way that you got from Frank. What were some of the things that you picked up from him?

Epps:

One of the things that I really enjoyed that I try to convey to my students is the enthusiasm and excitement for doing the research, and not just understanding the questions that we're trying to answer and understanding the why of certain things. One of the things that I try to instill in my students is every experiment might not have worked out the way that you wanted it to work out, but every experiment can work and tell you something. And so you might find that we've started out in one direction, but you do an experiment if you really analyze your results, that can help you solve a problem, and in some cases, doing an experiment and having it "not work" might help you progress a whole lot faster than if your first ten experiments work right out of the gate. So, really just understanding what you're trying to do, conveying that excitement, working together as a team. One of the things that I like to do is sit down with my students and say, "Okay, let's go through this. Let's see if we can figure out what happened, what went wrong. What didn't work out the way that we expected? Why didn't that happen?”

The other thing that I think is really important that I learned from Frank is attention to detail and how to present and how to write. One of the things especially these days is that the first impression that many people get of you before they meet you in academia, is they read a paper of yours. Or they see a presentation. And so that first impression really comes across in how you write, how you convey your ideas in that presentation setting. So really focus on honing those skills… The first paper draft that I submitted to Frank, I worked on it for a while, and I thought it was great. I really did. And he came back and he said--, at that time we were still printing things out, so I had handed him a printed copy-- "Hey, well, can I get an electronic copy?" And I said, "Well, sure, why do you need that?" And then he came back with two things. The draft that he gave me back didn't... I'm not sure if it had any of the words that I had in my original document. And he also then suggested, "Oh, well, maybe you should consider taking a writing course." And the good part is, and this is one of the things about him, is understanding different people and how people would take things. I'll get back to that in a second, but I took that and said, “Okay, I really need to work on this.” And I was able to work on it and improve. I'm not saying that I'm a good writer today; I'm definitely much better than I was then, but it's one of those things that you can keep working on and not become complacent. But the other aspect of that was understanding that everyone is different, and so he did tell me later, he said, "You know, I could give that to you and tell you that you need to maybe take a writing course because I knew that that would drive you to do better." For someone else, he might think, “I can't necessarily do that, because of how they would take it." So really understanding that as an advisor, that I'm advising a-- yes, there's a project, but I'm advising a person. And everyone's different, and so I need to figure out how to connect with each student. I’m not always successful, but I really try to figure out how I can connect with the students the best I can.

Zierler:

Thomas, I'm curious if you can set the stage on day one. I get the sense that there is an avalanche of responsibilities just sort of facing you out of the box. All of the courses to teach, all of the research projects to join, all of the students to work with. How did you navigate that from the beginning in terms of figuring out what's the best way for you to structure your day so that you can be maximally useful from a departmental perspective? You can maintain your own research, and you can be effective as a mentor and teacher to students. How did you sort of endeavor to put all of that together, sort of right from the beginning?

Epps:

I guess I was a bit lucky in a few respects. One of the things that I mentioned was my colleague Millie Sullivan, who started the same day that I did and her office was next door. One of the things that our department chair at the time, Mark Barteau, probably figured out, is that I think both of us appeared twice as smart as we were, because what we did is we would always come together and then one of us would go ask the questions. So essentially, we only ever asked half the questions, so he was probably like, "Okay, well these two at least halfway know what they're doing." But that was very nice in the sense that one of the great things about Delaware is being a very collaborative and collegial environment. Even starting from Day One, I didn't feel like I was competing with the other new hire that was there at the same time. We felt we could collaborate together as assistant professors and get started that way. Working with some of my other colleagues in terms of, as you mentioned, trying to figure out how to allocate my time to teaching, research, getting the lab started, etc. I've already mentioned Norm Wagner, who was just down the other corridor, very easy to walk into his office or he was next to Anne Robinson at the time, who's now at Carnegie Mellon, but she was also a great colleague that I could come to, ask questions on how to get started. Eric Furst, who is our current department chair at UD, was another person. So, it was really an opportunity to do some reading, do some learning on our own, in terms of figuring out what to do, talk to some of our advisers at other locations. Some of the friends that we had met at conferences, but really the department was very focused on helping us succeed. Whether that was through setting up team teaching-- I started out team teaching a polymer science course, and so that allowed me to really get into the mindset and the framework of teaching, but at the same time, with a course where-- it's great, because I still learn something every time I teach it, but I had a reasonable foundation in the particular subject matter. But I think the one thing to get across was that having good colleagues made it, I won't say easy, but definitely as smooth as possible.

Zierler:

What are the considerations in terms of setting up your own lab versus setting up a research center?

Epps:

So you mean in terms of starting out a lab or...?

Zierler:

Yeah. Like, the vari-- you know, you have students and you have a lab but then you might think that there's something bigger and there are some more interdisciplinary opportunities. What are the considerations for when you say, "You know, I think I have a lab on my hands here," versus, "I think I have something bigger than that that requires a broader collaboration?" What are some of those factors that decide that?

Epps:

I will say that I'm still navigating that, so I don't have a full answer, but I think one of the key words that you hit on in your question, was "collaboration." When we start thinking about these large research centers, they're interdisciplinary by nature, at least hopefully, and ours are. We really want to provide space where people from multiple groups can come and work together. From that standpoint, we're thinking about space where we can co-localize a group of people, where we can really have synergistic idea generation, have maybe core facilities and core equipment that everyone can use, and the space argument is also a little bit different. And the reason for that is because in many cases, we're looking to get space across departments, across colleges, and so the logistics are quite different. I would say one of the things that is a little bit less stressful is that, at least from the center standpoint, hopefully everyone already has some research space in which they can operate. So, you're not starting from ground zero, but then there are also those additional challenges of working across traditional lines. One of the nice things about centers is that we're not ‘siloing’ them in a department, in a college, sometimes not even within just one university. But, trying to navigate how to talk across different institutions, different organizations, which can be a bit of its own challenge.

Zierler:

In what ways did joining the faculty at Delaware provide you an opportunity to take on new research of your own, and in what ways did it provide you an opportunity to continue on the path that you had been developing from graduate school through your postdoc?

Epps:

Well, in terms of the second part of that, we were able through my research experiences to develop some nice problems that we were able to solve, that we felt could have an impact. One of the things that Delaware did to help was have the infrastructure in place. The characterization equipment, the proximity to NIST, some of the theoretical collaborators that I could potentially work with. From that standpoint, having that enabling infrastructure was instrumental. For some of the new areas that we were able to enter, that boils down to collaborative spirit. Delaware is a relatively small campus in terms of footprint, and that really allows people to walk very easily to someone's office, sit down, and have a conversation, start up a collaboration. And the model that we use is just very nice in terms of allowing joint graduate students, joint postdocs, joint undergraduate students across multiple research groups, which really facilitates those activities. That has allowed me to get into things like drug delivery and gene therapy, which is not something that I would have originally gotten into on my own; I learned from people like Millie Sullivan and April Kloxin; also get into more neutron scattering. Even though I was at NIST, I never performed neutron scattering experiments during my postdoc. I didn't start doing neutron scattering until I became a faculty member at UD, working with people like Norm Wagner and Darrin Pochan, etc., who were and are still leveraging neutron scattering. Even some of our newer endeavors into polymer composites with metal organic frameworks. One of the nice things about UD is being close to the Army Research Lab and the Combat Capabilities Development Command Chemical Biological Center, which are about 40 minutes down the road. There are a lot of opportunity to work with various institutions. In our case, we’ve had collaborations, for example, with Chemours, which is now located on UD's campus. So, it's a 15-minute walk to get to Chemours, or DuPont, which is a 15-minute drive, working with some of the other companies that are local, Gore, etc. that are right down the street. I don't have an active project with Gore right now, but we're working on some potential opportunities. It's the proximity and the openness to collaboration. And that is instilled throughout the whole process. So even when you think about, as an assistant professor, promotion and tenure, for example, you know, at UD, you don’t have to do everything on your own. Collaborating with others, getting joint grants; you get credit for that. It's very much encouraged to have an impact and not necessarily just stay in a silo, for example.

Zierler:

Now, you became affiliated with the Delaware Biotechnology Institute, DBI, right from the beginning.

Epps:

Yes.

Zierler:

I wonder if you could talk a little bit about over the course of the past 14 years, what have been some of the most exciting developments in biotechnology from a chemical engineering perspective?

Epps:

Oh, that's a little bit of a hard one for me. Let me first back up. You mentioned that I've been affiliated with them since I got started. That's one of the nice things about UD that I'll mention; the reason I became affiliated is because I wanted a piece of equipment, a small angle X-ray scattering instrument; it is a relatively expensive instrument. So, the department, the college, and the university got together and said, "Well, how can we fund this, how can we leverage it?" And one of the ways that they were able to do that was to get some funds from the Biotechnology Institute to help support it, which also gave me access to the Biotechnology Institute, while also allowing other researchers at UD to basically learn more about their nanostructured materials for things like drug delivery. I don't want to step on my biomedical or biomolecular engineering colleagues' toes, or even some of my biology friends' toes, and tell them what I think are their key advances, but I will mention a few things. One of the key things that we've been focused on is imaging technology. So really understanding when I take materials and put them in the body, for example, whether it's drug delivery materials, etc., where do they go? How do they work? Really understanding that allows people like-- we have some new colleagues-- or I shouldn't say "new," they've been there for six or seven years now, but people like Emily Day, that are working on how do I really design new materials for nucleic acid delivery… Kristi Kiick in terms of how do I design some new elastomeric peptide systems that can really-- with Xinqiao Jia, make some next-generation vocal-fold tissues and other biomaterials. Understanding how structure and properties work with the body etc. allows us to make some significant advances. In terms of biotechnology, I focused a little bit on the biomedical engineering aspect, but there are also the aspects of plant biology that go on in the Biotechnology Institute, such as looking at arsenic content in rice. How does it get there? How do you prevent it from getting there? There are a lot of fun projects where, again, looking at how do we image, how do we figure out where things are in various systems, which are quite nice. And one of the exciting aspects of that is, our USA Manufacturing Institute, called NIIMBL, that's focused in pharmaceutical development. So, not only how do we undertake the academic aspect, but how do we translate that to potential production? Whether that's vaccine production, whether that's therapies, etc. So, a lot of exciting things, but if I had to pick one naively, I would say it could be focused on how do we image systems so we can learn more about behavior and basically do more de novo-type design.

Zierler:

Thomas, can you talk a little bit about some of the major objectives of the Center for Fuel Cell and Battery Research, and what your area of expertise contributes to those broader objectives?

Epps:

In that case, I would say that I'm a bit of a minor player in one sense, because there are a lot of people doing great work in terms of designing things like fuel cell buses, designing fuel cell membranes. And so Ajay Prasad is one example of someone who's done some really great work, and you can even see that in some of the fuel cell buses that are going around campus these days, which his researchers helped engineer and test. In our case, we've been focused on battery membranes. We are trying to make membranes that allow batteries to be more efficient, to last longer, be lighter weight and easier to process. We really try to leverage our expertise in nanoscale materials. For example, how do we design material that has a particular nanostructure, because we can use that nanostructure to enhance transport? Or reduce dendrite formation? One example of why dendrite formation is important to understand is that if you're familiar with the hoverboards that were catching fire and got banned a few years ago, that's one instance where short circuiting in batteries was possibly leading to fires. There was a fire on an airplane in an auxiliary power unit, thankfully I believe that plane was on the ground at the time. But that sort of incident... I haven't flown recently due to the pandemic, but there were announcements in the past about, "Make sure you remove your spare lithium batteries, for example, from your checked luggage." So, one of the things that we're working on is, can we design safer batteries so that I don't necessarily have those safety concerns, at least as much anymore as we've had in the past.

Zierler:

How self-consciously is the center thinking about fuel cells and batteries as a specific response to carbon emissions and climate change? Is that sort of part of the equation, or that's secondary to the basic research that would exist even without concerns about carbon emissions?

Epps:

I'll say a couple things. I think part of the goal is to advance science and advance engineering, and think about how we can make more efficient materials. So, the ultimate goal is designing something that is more efficient, safer, lighter weight, more resilient, and longer lasting. I think that there are definite advantages, or potential advantages, in looking at environmental impacts. If we can design something that's safer, lighter weight, and more efficient, and also then potentially reduces carbon emissions, reduces materials going into landfills, I think that's a good thing to focus on-- or human health, so in terms of reducing waste products that can get into rivers and streams. It's a good opportunity to leverage both of those things. I wouldn't say that most of the projects necessarily go in with, "I'm just going to reduce carbon emissions," but it's, "Can I make something more efficient?" And one of the goals along with that might be, if we're able to do this, then we can reduce carbon emissions. And we sometimes work with our Center for Public Policy on what are the potential opportunities? For reducing emissions, etc.

Zierler:

Can you talk a little bit about your tenure as director for the Center for Molecular Engineering and Thermodynamics? I'm particularly interested in, we've talked about thermodynamics already, how thermodynamics is a starting point for so many areas of research, and how your perspective on that might influence the way you teach thermodynamics, the way you collaborate with your peers from a thermodynamics perspective. Can you talk a little bit just generally about your research and how it is shaped by your tenure as director of this Center?

Epps:

Yes, first, I’ll give a little bit of a plug for molecular engineering and thermodynamics and why it's important, and how it frames some of the things that we do in the center. When I think about, let's take toothpaste. Or lotion or soap. You take your lotion and you rub it on your skin, there's a certain consistency you want. You don't want to have it squirt onto your hand, you start rubbing it, and it drips all over the place. But then you also don't want lotion that's going to behave like toothpaste. And so, a lot of that revolves around, how does it phase separate? How does that phase separation change when it comes in contact with your skin, which may be warmer than the bottle? How does it change when I shear it? There are a lot of opportunities in consumer care and everyday products that are impacted by molecular engineering and thermodynamics. When you look at things like military clothing, for example, and you look at how do I make something that, in the case of our research group, we look at how do I make something that protects a soldier from, say, chemical weapons, but at the same time is breathable? How do I control evaporation? You might say, well, is that a huge difference? But yes, if I'm in the desert, and I'm wearing something that's not breathable, and I'm out there for eight hours a day, you can imagine that that's a pretty heavy burden on any human soldier. And we’ve talked about things like drug delivery, looking at what is the concentration [of drug] that gets into a cell or that doesn't get into a cell. If I put a drug carrier in the body, does it hold its shape or does it fall apart? A lot of that is understanding the thermodynamics. When you look at waste and where does it go, does it partition into the water? Does it partition into other environments? A lot of that is understanding, again, the thermodynamics of various systems. Those are some broad examples, but that's part of the beauty of thermodynamics, is it really impacts everything from medicine to consumer care to battery membranes to military equipment to waste production and waste cleanup. In terms of how it's impacted my group, I just gave some examples when I talked about military equipment and drug delivery, etc. So we've had some partnerships between people in the center and various companies, as well as some national labs. So really understanding a bit more about what the applications are and how we can use our understanding of that phase behavior etc. to really help advance applications and design that next generation of materials.

Zierler:

In what ways has being affiliated with the DOE's Energy Frontier Research Center, in what ways has that presented you, your students, Delaware, generally, with opportunities that might not have existed otherwise?

Epps:

Let me give a little bit of a plug to Delaware. We are one of the few places that is not a national lab that has two EFRCs. That's a major accomplishment. The one that I'm deputy-directing does not officially start until August 1st, so I can't say too much about that. But your question gives me the opportunity to give a plug, and then talk about our other one. We have one that's the Catalysis Center for Energy Innovation, run by Dion Vlachos. And that one is focused on, how do I use products from biomass, etc., and turn them into valuable materials. One of the nice things about that center, is that it's been very open to addressing how do we think about valorization and the evolution of that process. It started off being extremely catalysis-focused, for example, how do I design new catalysts? How do I understand transition states? How do I model that type of process? And they're still doing a lot of that work, but one of the things that they've realized is that there are a lot of opportunities for valorizing that process when I start making materials and start making new plastics that are potentially more environmentally-friendly and have a better life-cycle footprint. So basically, can we go from renewable feedstocks to recycling those materials? One of the nice things about the EFRCs is the opportunity to bring people together to think about everything from just fundamental catalysis all the way up to, what are possible applications for those end-product materials, lubricants, small molecule additives, etc.

Zierler:

I can't help but say out the delightful acronym, the Center for Hybrid Active and Responsive Materials, CHARM. Who came up with that lovely acronym?

Epps:

So that was me. One of my crowning achievements, because I think it's the only acronym I've come up with that people have actually used. Usually most of the others gets axed at the drawing board.

Zierler:

What are Hybrid, Active, and Responsive Materials? What's the overall understanding of this?

Epps:

What we're interested in is two-fold. The first aspect is soft materials, so molecules like polymers and peptides, such that when you press them, heat them, etc. you can get some sort of response. We're really interested in combining polymers and peptides to make molecular machines and molecular motors. Small, nanoscale things that can move a protein from one place to another, for example. Maybe repair a little blemish on a circuit board. We're obviously not there yet, but you can think of something like Ant-Man, where I can basically shrink something down to a more molecular level and create a molecular machine. So, that's one aspect. The second aspect is hard materials, quantum materials, and trying to develop that next generation of sensors and detectors. Things that can sniff out a chemical warfare agent at a really small concentration from far away. Help with airport screening or even virus detection. For example, maybe can we detect even smaller quantities of a virus, whether that's on a surface or potentially as we look at testing associated with the coronavirus, can we make instruments that are more sensitive and more accurate. A key challenge is combining different types of materials and taking advantage of the hybrid interfaces that come from having different types those of materials interacting. Can they guide light better? Can they guide electricity or guide sound in a different and more efficient manner?

Zierler:

Well Thomas, now that we have brought your research in terms of the narrative literally right up to the present, I mean, August 1st is merely days away from the launch. You already mentioned it, I want to talk, before we get to my last question, which is a sort of forward-looking question about things that you're thinking about for the future, I do want to touch on two sort of broadly-current issues. And the one you already mentioned, of course, is coronavirus. It's very, you know, with all of the tragedy that's happening right now, one thing is, it's very exciting to see all of these remarkable scientific collaborations that are happening, you know, essentially on an emergency basis, and they're unfolding in real time, and the moment really demands for new thinking in collaborations that may not have existed before, because of the immediacy of the challenge. And so I ask, it seems that you're involved in more scientific endeavors than you're not, and because you have this long-standing expertise in thinking broadly and innovatively in all areas of research, I wonder if you could speak specifically about what your own area of expertise and what chemical engineering generally might have to offer COVID-19, either in terms of vaccines, in terms of therapies, in terms of testing, in tracing? What are some of the ways in which your field and the institutions that you're involved with might be able to productively contribute to this worldwide effort?

Epps:

Yes, I think that there's an opportunity for chemical engineering to have an impact on all the things that you mentioned. So, let's start by going through vaccines. One of the things that, as a chemical engineer, and as a part of that community, is really understanding the basics of cellular behavior and cellular processes. How things get into cells, understanding the kinetics and the transport associated with those processes. Then, taking our skillsets and whether it's drug delivery, overcoming cellular transport barriers, interacting with cellular receptors, in terms of a virus, looking at, say, a vaccine and understanding what types of adjuvants do we need to use. Looking at the kinetics of that process, etc. One of the challenges that you hear about in the news, is that once we get a vaccine, how do we scale it up in terms of mass production? How do we produce it quickly? That's a nice chemical engineering problem in terms of scale up and reactor design. Then, thinking about modeling… kinetic modeling, of not only the viral infection or the vaccine interactions, but thinking about transmission from a systems engineering standpoint, and optimization standpoint, is also something that really fits... Chemical engineering can play a large role. When you think about disinfecting surfaces… surface energy, One of the ways that many disinfectants work is to rupture a cell wall or cell membrane or a virus capsid, so, how do we design different types of surfactants that might work better, be longer-lasting, potentially kill the virus on the surface even without, say, a liberal application of cleaning spray? Or when thinking about masks… Many of them are either disposable, or we have to wash them, for example, to remove the virus. Can we start thinking about designing masks with materials that are anti-viral on their own? Such that they kill the virus, as opposed to just potentially blocking its spread? There are a lot of opportunities for chemical engineering to play a role, and I probably missed some, but I just wanted to give you a flavor of some of the different aspects-- well, I'll mention two things. So, sensing and detection is also important. Tom Gutshall, who with his wife Kipp, are supporting my named chair-- are involved with a company that had one of the first rapid virus-detection tests. And so again, he's a chemical engineer, graduated from the University of Delaware, and there's a lot of opportunity in that space as well. One of the nice things that I've seen, as you pointed out, is that collaboration, and not just the academic collaborations, but also we're hearing some nice reports of companies that are collaborating to come up with vaccines, etc. Collaboration is a nice model to get things done, and the pandemic is providing an opportunity for people to come together.

Zierler:

The other broad current events issue I wanted to touch on and get your perspective on is, you know, we're still only a few short weeks away from the events leading up to #ShutDownSTEM. I would like to hear your perspective on what you thought the significance of that day was. I ask this question because my understanding is, is that if we treat this simply as a day on the calendar and we just continue to move farther and farther away from it, we miss the point of what that day was supposed to be. And so, my question is, drawing on your own experiences throughout your education, all of your research and professional accomplishments. What do you see as the most positive and productive way to take the opportunities of that moment and the moment we find ourselves in as a country, and use that to increase the vital importance of making STEM as inclusive and diverse as possible? Both in your role as a mentor to students, as somebody who's greatly respected by your colleagues, and as someone who's young and has a very full and long career ahead of you, where these topics are going to change and hopefully for the better?

Epps:

Yes, I think there are a few things there. The first thing is that hopefully it's an opportunity to recognize that there is a problem that needs to be addressed. And I think that part of it is whether you-- there's the inclusiveness, there's the systematic bias, and that doesn't necessarily say that an individual is biased. It's saying that the system is set up in a way that is not equally beneficial to all. I think part of the issue is recognizing that, as the first step, and then looking at how that can be changed for the better over the longer term. What I mean by, "over the longer term," is that there are a lot of little things that people are doing in the short term, and then saying, "Okay, we did something." And while that's good, I think that when you look at things like #ShutDownSTEM, it's an opportunity to think about, what can we do over the longer term that is going to get it started today but hopefully have an impact in 5 years, 10 years, 20 years, and continue moving us forward? I think that's one of the main things that we really want to focus on, and I think it's also important from a sense of community, because one of the big things that can really help is having a sense of community where everyone feels like they can belong and be open about their challenges and their opportunities. We're finding from listening to stories that there are some challenges associated with community. One of the big things that I'm hopeful about, is we've heard many horror stories, and it's interesting because as an African-American, we're telling the horror stories now, but that doesn't mean the horror stories just happened. They've been happening, and they continue to happen. I think it's an opportunity for people to hopefully open up and hear what's going on, and realize that it has been going on the whole time… and understand that this is the time to potentially do something about it. So, really become an ally and say, "Okay, I can continue to be myself and do my things, but I have an opportunity really to broaden the community and help someone else. That doesn't mean help someone else and harm myself. That just means that I can do my things and also help someone else succeed, too.” And figure out how to do that. Whether that is through increased scholarships, increased learning opportunities, thinking about, “we have this rule that only benefits certain type of people, or in many cases, not that it necessarily is designed to do that, but it may unintentionally harm others. So, are there ways that we can restructure it?” Whether it's around the promotion and tenure process, or admissions for students to undergraduate opportunities, etc. I think this is a good opportunity to think about it. I've stayed away from some of the more horrible things that have happened, but it's an opportunity to address those issues and figure out if we can do our best to eliminate all of those things from society.

I'll point out some of the things that we're doing at UD, and again it's not that we're perfect, I don't think that any institution is, but-- we have research town halls associated with COVID, but one of the things that our vice president for research starts off with, is STEM and talking about inclusivity and in this case, thinking about some of the Black Lives Matter issues, he puts that as a hashtag on his slides when he gets started. And also talking about some of the gender-related issues. I think that keeping those things in the forefront is good, because it allows us the opportunity to figure out what we want to do moving forward.

Zierler:

Thomas, I wonder if you could reflect on, it's remarkable to say, but going back to when you started at MIT, that's 25 years ago, right? In what ways, if you can reflect on your own experiences, and obviously your vantage point is very different when you're experiencing things in real time and when you look back on them as a professor today. In what ways in this perspective on inclusivity and diversity, in what ways does 25 years feel like a long time ago, in terms of social mores, in terms of the way that you may have been treated by fellow students or professors, and in what ways does 25 years sort of feel like not so long ago? Because things might not have changed so much in the intervening time?

Epps:

Thanks for that question. It's pretty much all of the second and none of the first-- in that we tell stories about things that have happened 10 or 15 or 20 years ago, as opposed to necessarily something that happened yesterday. And one of the reasons for that is not because nothing has happened in the last 5 or 10 years. It's just that once you reach the point where you've lived with a specific incident for say 25 years, it becomes a bit easier to deal with, so it becomes a bit easier to talk about. I do want to provide a word of caution going back to the inclusiveness and the STEM discussion, that because people talk about history or events from a longer time ago-- It's just because it's more comfortable, not that things haven't happened in a more recent time period. Here’s an example, I'll tell a story from when I was at an event where older alumni were meeting with some of the senior students at MIT. I was talking to an older lady who came up to me and another student, and she turned to the other student who happened to be white, and said, "So, what was your major?" And he said chemical engineering, and so they talked for about 10 or 20 seconds about what he did. And then she turned to me and she said, "What sport did you play?" And that's the--

Zierler:

Well, you could say baseball, right? (laughs)

Epps:

Right? But the ironic thing was, yes, I played baseball; I was pretty good. But I was also one of the top students in my class in chemical engineering, and so she had asked one of the top people in the class what sport did I play. And she had asked a Division III All-American football player candidate what his major was. It was doubly ironic from that aspect; those types of things are pretty innocuous thing from one standpoint, but it's evidence of the sort of bias that exists, and that still exists. Even when I was in grad school at Minnesota, I can't count how many times I was asked if I was on the football team. And you can see me on Zoom, I'm not a big guy.

Zierler:

No, and you're also so clearly a science guy, too. I mean, it's just... that much be just so-- And what is, I mean, do you contain yourself? Do you let people have it on the spot? I mean, what's your general reaction with these sorts of micro-aggressions, even if people are meaning well but they're just biased because this is the society we live in, what's your response? And what advice might you have gotten from your parents in terms of their own abilities to navigate these kinds of issues during their time?

Epps:

There are two things-- or at least two, but the two that I'll mention… and this does get back to parents. One of the things that they have taught me, and I use "have" because they taught me and they still continue to remind me to this day, is how to not over-react to those sorts of slights. And that doesn't mean that when those things are said that they have no effect, but it just means that it's something that you have to contain yourself over. Because to be frank, they happen every day, so you know, if I'm going to--

Zierler:

And you mean that literally. You mean they happen every day.

Epps:

I'm being literal.

Zierler:

Yes.

Epps:

They happen every day. So, it's a very short life if you react to every one of those.

Zierler:

Right. You're going to have a blood pressure issue if that's your response.

Epps:

And the second thing, which is somewhat unfortunate, but it's worth mentioning is that when something like that situation that I mentioned happens, in terms of the grand scheme of things that I have seen that are biased, it is so low on the level that it-- and especially from some of the things that I saw happen to my parents, etc., that it literally is not-- I don't want to say it's not worth a reaction, but it's almost not worth a reaction on the relative scale of things. Which says two things. First, that's sad because you know that that's not worth a reaction, but, second, it also sets the scale for things that people have seen and not necessarily talked about that have happened to them, their family, their loved ones, their community, etc.

Zierler:

There's a range of responses that I've found from scholars who come from under-represented groups in the moment that we find ourselves. Some people are very out in front of the issue, and they're writing on blogs and they're active on social media, and it's become a very big part of their professional identity. And on the other range, there are people that are, you know, they just want to do the science. And that's their professional identity and if they find themselves as leaders, it's because of where they come from but they want to express themselves primarily as scientists. Where do you see yourself on that range?

Epps:

I think that everyone has to do what-- not saying that everyone has to always be comfortable, because to some extent, if you're comfortable, maybe you're not necessarily moving forward-- but everyone has to do things that they're comfortable with. In some cases, that is being vocal or blogging about it all the time. In some cases, it's just about doing science. I would say for me, I'm somewhere in the middle. I have a twitter account (@TheppsMIT). I do use it, but I keep that to mostly science. When I'm thinking about things within my department, within my university, within the organizations with which I'm involved, there I will be a little bit more “pushy,” so to speak, on what are we doing to address some of the disparities that we're hearing about in society? And so, I would say that I'm a little bit more behind the scenes-- I definitely focus on my science, but I think that I'm very focused on providing additional opportunities… through activities like the American Chemical Society Project SEED and ACS Scholars Programs. I started the Project SEED site at the University of Delaware, which provides high school internships for students from underprivileged groups, both socioeconomic as well as the underrepresented minority. I've also focused on an NSF Future Faculty Workshop Program that I run with LaShanda Korley (at UD) and in this past year with Rodney Priestley (at Princeton), where we're really focused on talking to people from underrepresented groups… minority as well as the women and people with disabilities in terms of explaining the unwritten rules of professorship. Things that they might not learn about otherwise. Basically, providing equal opportunity and leveling the playing field in the academia application process. I've been very focused on those types of initiatives, as opposed to tweeting or blogging, per se. But I think that's good, because there's a role to play in all three spaces. So, keep doing the science, do some of the outreach and educational activities, and also doing some of the calling out the situation. And in many cases, those three things can work together. But I would say that I'm somewhat in the middle.

Zierler:

Have you seen undergraduates or graduate students from minority groups who look at you and specifically say, "Because you're doing this, it occurred to me that I can do this as well"? In other words, how important is it from a student perspective to see diversity in the faculty in terms of exciting or encouraging their own professional prospects?

Epps:

I think that it's critical to see diversity. And the reason I say that is because, as an underrepresented minority, you can go through an entire curriculum or college experience without seeing someone that looks like you, and someone might say, well, is that really a big deal? And the answer is, yes, because it allows you to at least picture the fact that maybe “I could get there.” It doesn't mean you have to get there, but it just means maybe “I could get there.” If you can see that one person can do it, it's, "Maybe I can do it as well." That's very important in terms of having a picture or role model in the classroom. And that's one of the challenges at many places, when you look at some of the top chemical engineering programs… and I will say that there are some exceptions, but many of them if you look at the number of, say, African-American faculty in chemical engineering, it's a quite small number. You can look at places like MIT where there's a more significant number-- I'm not saying that there's an over-abundance by any stretch, but then again, you look at Paula Hammond and Kristala Prather and Fikile Brushett, but then you come to our university, University of Delaware, in chemical engineering, we have five African or African-American faculty. We are looking at, how do we provide role models, how do we provide opportunities? But also, how do we propagate good scholarship? Because if you look at those five faculty, one is new, so he's just getting started at UD, but, for the rest of us we've brought in that EFRC, the MRSEC, one is the Dean of the College of Engineering. The other one is the previous Dean of the College of Engineering. So, it's also about providing leadership and showing that we can still do great things. But we can all do great things.

Zierler:

Thomas, it's quite sobering but also quite important to hear you emphasize that reflecting on the past 25 years that the emphasis is more on things being the same than they're different. And yet here we are in this moment, where there is hopefully, I hope I'm not being naive, I hope I'm not being too optimistic, but it does seem like there is a moment here to ensure or at least to work our best so that in 2045, when I come back to you for another interview, right? You don't have to say, "I'm sorry to report to you, David, but now it's 50 years and things still look the same." Right? How do we prevent that answer from happening in 2045?

Epps:

That's where getting back to thinking about long-term planning is important. In a lot of cases, there is the easy solution. For instance, I love running. There are the easy solutions to, “hey, I want to run faster next week, so let me do a couple little things so I'm a pound or two lighter next week” versus, say, longer term, “how do I completely change my running structure so that I'm faster two years from now and from then on.” That's a bit harder conversation that takes more work and planning, and one of the things that I hope-- so coming back from the analogy-- one of the things that I hope happens is that we don't just do the short-term, okay, let's have a couple faculty or community discussions about what's going on and hear people's stories and then say, "Wow, that's awful. Wow. Okay, let me get back to what I'm doing." We should think about, can we develop strategic plans for improving this in the longer term? Can we sit down and think about, okay here are the little things we can do for tomorrow, but here are the things that we can do that if we follow through will really make a difference? Hopefully starting tomorrow, but even some that will take 10 or 15 or 20 or 25 years to bear fruit, but will lead to systemic long-term changes… The system wasn't created yesterday; it wasn't created 25 years ago, so expecting that it's going to be undone in a week or a month is a little bit of a challenging premise.

Zierler:

Thomas, for my last question, let's pivot to something a little happier, and we can be a lot more certain about. While we don't know what the world is going to look like from a diversity perspective in STEM, over the next 25 years, it's obvious that you have incredible things in your future. There's a lot that you're going to accomplish, and a lot of people, frankly, are excited to watch this remarkable career of yours really take off into the next phase. And so I want to ask, given the limits of time and resources and energy and all of the things that you're involved with, right? What are some of the top-line areas where on those days where you can focus on particular items-- not what you want to accomplish next week or next month or even next year. But the bigger questions about where your field is headed. From that perspective, what are the things that you want to accomplish when you think about in terms of decades?

Epps:

Okay, so first, I'll say that for anyone that's working with me, I love all of my projects, and I love everything that we're doing. I will start there. And then I'll say, there are some things that are particularly exciting for me in the longer term. When we think about the world that we live in and everyone we interact with, we think about how do we better-utilize our resources. So thinking about can we-- I don't want to say "eliminate" waste, but really reduce our waste and environmental impacts. Can we find ways to use materials better? We're really excited about our plastics innovation and using waste products and biomass, along with all of the designer materials that we can make from those systems that are going to revolutionize things like clothing, and make other light-weight, stronger, flexible, environmentally benign materials. I even have a-- I'll put in a plug for a start-up company that we have, called Lignolix, Inc that's focused on biomass valorization. Can we really utilize our natural resources in a sustainable, environmentally-friendly manner to make some new materials? The other thing is, when I think about what we're doing in terms of drug delivery and gene therapy, can we develop these nice, designer materials? Right now, we have the vaccine trials that are making the news with COVID, and they've been going on for, I guess, at least roughly six or so months, for example. But what if 20 years from now, if there is a-- what would that be? COVID-39. Then-- what if that were to happen, and someone was to say, "Okay, I have a sample," on Monday, and then by Wednesday they've plugged it into the computer, and we have a vaccine. Those types of things really excite me in terms of, can we really understand structure-property relationships? De novo designs so that we can really design specific things on the fly that can target specific systems. I would say those are definitely two areas. But the third area is thinking about energy. As we continue to advance technology, our energy usage, or number of devices, goes up, so thinking about camping, or other activities. My Garmin is great, we go hiking, and my Garmin will last two weeks. Sometimes, I have to turn it off in terms of GPS mode, but what if I could have it last a month or two months or not have to-- I had to take off my headset [during this discussion] because the battery was dying. What if I don't have to do that after an hour and a half. And in full disclosure, I forgot to charge it last night. But from that standpoint, when I think about energy, how can I do those things?... really have long-lasting energy supplies.

Zierler:

Well, Thomas, it's been an absolute pleasure talking with you today, and if we're both in the position, I mean it. I would love to circle back in 25 years. Mostly because I'd love to see how all of these goals have played out for you. It's remarkable, you effortlessly move between sort of basic science accomplishments and really having your pulse on what society needs from science. And that's a crucial question right now, and it's only going to get more important as time goes on. So I really want to thank you--

Epps:

Can I say one other thing?

Zierler:

Yeah, please.

Epps:

So one of the other things that I'm super excited about, just even tangentially related to the science and the question you asked, is that I like to see where, I'll call them, my "people"-- my students and postdocs, where they go and what they do-- and so in 25 years, hopefully I'm talking about, "Oh, I had this student back in 2006 who did this great stuff in my lab, but he's now running this big chemical company, and they have this cool process, or she has this great start-up that--" I've had students that have gone into start-ups, and I have a few that I think are going to be wildly successful. That, for me, is one of the really exciting things, not so much what the things that I'm doing are going to look like, but hopefully what the things that the people who are going to be better than me look like, and that's what I'm trying to get my students to be… going out and doing some really cool stuff.

Zierler:

Well, that of course also speaks to your generosity as a scholar for sure.

Epps:

Thank you.

Zierler:

Thomas, it's been so fun talking with you. I really appreciate our time and this is going to be a very important addition to our collection in the Niels Bohr Library, so I want to thank you again.

Epps:

All right, thank you very much.