Gina Kolata in The New York Times:
The idea sounds like fantasy: an invisible film that can be painted on your skin and give it the elasticity of youth. Bags under the eyes vanish in seconds. Wrinkles disappear. Scientists at Harvard and M.I.T. have discovered that it is not fantasy at all. Reporting on Monday in the journal Nature Materials on pilot studies with 170 subjects, the researchers said a “second skin” composed of commonly used chemicals deemed safe by the Food and Drug Administration can accomplish that — and in small studies of it, so far no one has reported irritation or allergic reactions.
Undereye bags are just the start. You can soak the film with sunscreen and protect yourself without worrying about sweat or water washing it away, researchers said. They expect it can be used to treat eczema, psoriasis and other skin conditions by covering dry itchy patches with a film that moistens and soothes. The chemicals are siloxanes — their basic form is one atom of oxygen linked to two atoms of silicon — which form polymers, long chains of repeating units. The researchers made a large collection of them by modifying molecular features such as the chain length to get the ones with the properties they wanted. Then they devised a two-step process. First, a polymer, a clear liquid, is applied. Its chains are not very strong, though, so the next step is applying a product that links them together. By modifying the chemistry of the chains, the researchers can alter the properties of the second skin, depending on how it will be used, making it more or less permeable, for example. A more permeable second skin might be used for undereye bags while a less permeable one might hold a medication in place. It can be removed with a solution that dissolves the polymer.