BACKGROUND: Researchers at Ohio State University have just completed the first comprehensive study of human hair at the nanoscale. Special equipment enabled them to get an unprecedented close-up look at what happens on "bad hair days": from chemically overprocessed hair, to curls kinked up by humidity. They then used the techniques they developed to test a new high-tech hair conditioner. These same techniques could eventually be used to improve lipstick, nail polish and other beauty products.
ABOUT YOUR HAIR: Your hair actually has a very complex structure. Each hair grows from a tiny saclike hole in your skin called a follicle. At the bottom of each follicle is a bunch of cells that make new hair cells, which add on at the root of the hair, causing the hair to grow longer. So the living part of your hair is hidden inside the follicle. The shaft -- the part we see -- is made of dead cells. So damaged hair can't heal the way living tissue can heal. You have to try to repair the damage, or cut it off and wait for more hair to grow back. Each hair shaft has two to three layers, most notably the cuticle -- which protects the inside of the shaft from damage -- and the cortex, made of long proteins that make hair elastic (it stretches before it breaks). The cortex proteins also determine your hair's natural color. People with coarse hair also have an extra layer of soft spongy tissue called the medulla.
WHAT THEY FOUND: The OSU scientists found that under an electron microscope, individual hairs look just like tree trunks, wrapped in layers of cuticle that resemble bark. When hair is healthy, the edges of cuticles lie flat against the hair shaft, but when hair is damaged, those edges begin to peel away from the shaft. When damaged hair is exposed to humidity, the hairs plump up and the cuticles stick out even further, leading to frizz. And more frizz means there is more friction, which can further damage hair.
WHAT IS FRICTION? Friction causes a lot of problems in hair, but what is it, exactly? It is the force that opposes motion, and is produced whenever two things rub against each other. Aerodynamic drag is a form of friction: it is created when the air surrounding a cyclist, for example, catches on the skin and clothing, slowing the cyclist down. The rougher an object's surface, the more friction that is produced when it rubs against something else. Washing, drying, combing and brushing all cause hairs to rub against objects and against each other. Over time, this friction causes wear and tear to the hair.