Role of selective sorption in chemiresistor sensors for organophosphorus detection

Nickel, palladium, platinum, and copper tetrakis (cumylphenoxy) phthalocyanines were combined with an elastomeric, oligomeric fluoropolyol material in mixed Langmuir-Blodgett films on chemiresistor sensors for organophosphorus vapors. The phthalocyanine carried the electronic current, while the fluoropolyol improved the sorption characteristics of the film. This strategy produced sensors with improved response and recovery times and high sensitivity. Factors influencing the selectivity of the sensor responses were analyzed in terms of two steps: sorption and transduction. Sorption was shown to be the primary determinant of selectivity among the organic vapors tested.