Glowing Polymers Detect Explosives

Three silafluorine-fluorine polymers can quickly and easily reveal the presence of minute quantities of explosives left behind on surfaces. Jason C. Sanchez and William C. Trogler at the University of California, San Diego, synthesized these stable, photoluminescent polymers through a series of hydrosilylation reactions between 1,1-dihydridosilafluorene and various diethynylfluorenes (J. Mater. Chem., DOI: 10.1039/b802623h). The researchers report that a thin layer of these polymers sprayed on a suspect surface can detect nitrogen-based explosives such as trinitrotoluene (TNT) after only 30 seconds. The polymers normally emit blue light when illuminated with ultraviolet radiation. The explosives absorb the electrons emitted by the illuminated polymers and quench the blue glow. The presence of as little as a picogram of explosive will cause this quenching, resulting in a dark spot on a film surrounded by the blue light from the polymers. Other explosives, such as pentaerythritol tetranitrate (PETN), emit a green glow when reacting with the polymers. The authors suggest that law enforcement officers could use this technology with minimal training to quickly and easily detect small amounts of a variety of explosives.