Octocrylene

Octocrylene is an organic compound used as an ingredient in sunscreens and cosmetics. It is an ester formed by the reaction of 3,3-diphenylcyanoacrylate with 2-ethylhexanol. It is a viscous, oily liquid that is clear and colorless.
The extended conjugation of the acrylate portion of the molecule absorbs UVB and short-wave UVA (ultraviolet) rays with wavelengths from 280 to 320 nm, protecting the skin from direct DNA damage. The ethylhexanol portion is a fatty alcohol, adding emollient and oil-like (water resistant) properties.
This organic compound can penetrate into the skin where it acts as a photosensitizer. This results in an increased production of free radicals under illumination.

This page uses material from the related Wikipedia article which is released under the Creative Commons Attribution-Share-Alike License 3.0.