A Polymer Coating That Can Heal Itself Thanks to UV Light http://www.nytimes.com/2009/03/17/science/17obheal.html?ref=science

For years scientists have been trying to develop a self-healing polymer for use on cars, furniture and other objects, which, like skin, after a crack or scratch occurs quickly heals itself. Many believed that the answer was to embed paints with microspheres that when broken in the act of a scratch or crack, chemicals flow from the tiny spheres into the void. Biswajit Ghosh and Marek W. Urban of the university of Southern Mississippi have come up with another approach, which incorporates not a sphere but a ring-shaped chemical, oxetane, that is incorporated in the polyurethane polymer. Another compound in the polymer, chitosan, forms cross-links at the laces where the oxetane breaks, healing the scratch. Given that the last of your car scratches receives plenty of UV light, which is used as energy to reform broken bonds, and has this amazing type of paint, that scratch could disappear before the next time you drive it. No more annoying and unsightly scratches!!!!