Conductive polymer-coated fabrics for chemical sensing

A novel sensing format for the detection of toxic vapors is presented. It uses thin films of conductive polymers, polypyrrole or polyaniline, coated onto poly(ethylene terephthalate) or nylon threads woven into a fabric mesh. Chemical sensing on fabrics offers the opportunity of using the large surface area for improved sensitivity and expanded dynamic range. The resistivity of these materials was monitored following exposure to several toxic gases. Detection limits in parts per million (ppm) were demonstrated for various pollutants and chemical warfare simulants, including dimethyl methylphosphonate (DMMP), ammonia, and nitrogen dioxide. The effect of humidity on the detection capabilities of these materials was also characterized. Polymeric overcoats including polyethylenimine and fluoropolyol were evaluated as a means of introducing selectivity and sensitivity with respect to the adsorption of particular classes of gas analytes.