Chemical Detection

As the U.S. is engaged in battle overseas, there is an urgent need for the develop-ment of sensors for early warning and protection of military forces against potential attacks. On the battlefields, improvised explosive devices (IEDs) have resulted in 54 % of all coalition deaths in Iraq and 59 % in Afghanistan. The U.S. military has re-sponded with an intensive program of technology development, spending $12.4 billion over the past three years on counter-IED equipment, technology R&D, training, and other measures through the Joint Improvised Explosive Device Defeat Organization (JIEDDO). “Sniffing”technology, based on fluorescent polymers, has emerged as one of the most sensitive tools in the military’s explosives-detecting arsenal. Fluorescent polymer sensors have demonstrated effective ultra-trace, vapor-phase detection of trinitrotoluene (TNT) at security checkpoints and during vehicular sweeps, achieving sensitivity levels comparable to the canine nose. In this sensor scheme, a large contri-bution to the noise signal is the inefficient transduction of the polymer’s chemically sensitive, photoluminescent signal into an electrical signal. The poor optical couplin