Everyone knows that if you swim or soak in a tub for a long time, your skin turn all pruny but have you ever considered how the skin doesn’t simply dissolve? It’s all in the keratin:
After a period in water the outer layer of the skin (the stratum corneum) expands, producing prune-like wrinkles. Earlier researchers suggested the stratum corneum expands as it absorbs water, but no one had yet explained why skin doesn’t fall apart when it has expanded.
Keratin is known to prevent evaporation from the skin and to absorb water to help keep the skin hydrated. The stratum corneum layer also gives the skin its stretchy properties and the ability to spring back.
Using computer modeling Evans approached the question from a geometric point of view to try to explain why skin maintains its structural rigidity after long exposure to water. She said the outer layer of skin contains a three-dimensional pattern of keratin fibers woven together to form a structure capable of acting like a sponge.
The fibers are helical when dry but straighten out as water is absorbed, which allows the network to hold a greater volume of water. All the contacts between the keratin fibers remain intact throughout the expansion, and this makes the material structurally stable, Evans said.