Developments to Watch
PHOTOCHEMISTRY GETS DOWN TO `BASICS'
Computer chips and dental work have something in common: Both rely on photochemical reactions. After spreading dental putty, dentists use a blue light to trigger a rapid hardening. Similar chemistry is key to printing circuits on silicon--only the light is ultraviolet. In one common type of photochemistry, light sets off a reaction between a light-sensitive molecule and a polymer, forming cross-linkages in the polymer. The light-sensitive molecule is either an acid or a "free radical," a substance with an extra electron.
Charles Kutal, the University of Georgia's chemistry department chair, is developing a whole new type of photochemistry. He's making light-sensitive molecules that are bases, the opposite of acids. He says acids can linger, causing corrosion. And reactions involving free radicals are inhibited by oxygen. Bases have neither of those problems. Kutal's research team has developed "basic" epoxy compounds that could be used for dental work as well as for chip circuitry, coatings, and inks--and even sutures for eye surgery. He says several companies have expressed interest.EDITED BY RUTH COXETER