The design of functionalized silicone polymers for chemical sensor detection of nitroaromatic compounds

A series of novel chemoselective polymers have been designed, synthesized, characterized, and evaluated as sensor coatings for the detection of polynitroaromatic compounds. These polymers have been evaluated as thin sorbent coatings on surface acoustic wave (SAW) devices for their vapor sorption and selectivity properties. The most promising materials tested, include siloxane polymers functionalized with acidic pendant groups that are complimentary in their solubility properties for nitroaromatic compounds. The most sensitive of the new polymers exhibit SAW sensor detection limits for nitrobenzene and 2,4-dinitrotoluene at 3 parts per billion (ppb) and 235 parts per trillion (ppt) respectively. Optimized polymers exhibit low water vapor sorption, and rapid signal kinetics for nitrobenzene, reaching 90% of signal response in 4 seconds. Studies with an in-situ infrared spectroscopy technique are used to determine the mechanism of interaction between nitroaromatic compounds and the chemoselective polymer.