Viologen polymer-coated impedance sensors for midrange humidity levels andother volatile organic compounds

We have demonstrated a sensor based on an interdigitated electrode platform coated with a conductive viologen polymer that has excellent moisture sens itivity, response time, and low power consumption. Work has been done to ex plain the limits of sensitivity and characterize the response of the sensor in low-humidity and also characterize the response of the device to variou s organic interferents such as alcohols and organophosphonates. Using lumpe d-circuit models, the nature of the response is explained and design parame ters are isolated that will allow future performance improvements. In addit ion, the temperature dependence of moisture sensitivity is presented. (C) 1 999 The Electrochemical Society. S0013-4651(98)01-031-3, All rights reserve d.