Tapping the power of lightsticks

August 21, 2006

Scientists have applied the principle behind lightsticks -- those snap-to-glow devices that light up without electricity -- to produce remote photopolymerization, a long-sought process for sealing inaccessible cracks and numerous other potential practical uses.

Douglas C. Neckers, Andrei V. Fedorov and Andrei A. Ermoskin report a demonstration of remote polymerization, or "remote cure," in a study scheduled for publication in the Aug. 22 issue of the ACS journal, Macromolecules.

Photopolymers are the basis of multi-billion-dollar industries, with uses that include clear coatings, paints, varnishes, adhesives and sealants. These liquids change or "cure" into solids when exposed to light. Chemists have speculated for years about an apparent contradiction in terms -- the possibility of having photopolymerization happen without light or heat.

Neckers, Fedorov and Ermoskin have demonstrated that photopolymers will harden in the presence of the chemical reactions that make lightsticks glow. They propose "remote cure" as a name for the process and cite several possible applications. Among them are sealing joints, cracks or holes inside pipes, tubes or containers where light cannot reach. "Another utilization of remote cure might be to cause the formation of a coating behind a pipe or in a room that could not be entered because of contamination."

Source: American Chemical Society