Recent developments in sorbent coatings and chemical detectors at the naval research laboratory for explosives and chemical agents

New chemoselective polymers have been developed to enhance the nitroaromatic sorption properties of coated acoustic wave (AW) devices. The sensitivity and selectivity of polymer-based sensors depends on several factors including the chemoselective coating used, the physical properties of the vapor(s) of interest, the selected transducer, and the operating conditions. Detection limits with the coated SAW sensors, tested under laboratory conditions, are determined to be < 100 parts per trillion for 2,4-dinitrotoluene (2,4-DNT). A new SAW based chemical vapor detector the NRL p-CAD has been developed with dramatically improved signal kinetics offering T-95 response times of less than 0.1 second for a wide range of organic compounds including the nerve agent simulant and agent precursor material dimethylmethylphosphonate. In addition, the NRL p-CAD system offers a rapid 2s baseline reset virtually eliminating baseline drift issues associated with changes in temperature and relative humidity. The p-CAD system has been successfully tested in both ground and unmanned aerial vehicle (UAV) testing.