Development of electronic nose using chemiresistive percolation network gas sensor based on conducting polymers

Abstract

A method of producing poly(3,4-ethylenedioxythiophene) (PEDOT) explosive percolation (EP) gas sensor with ultra-fast response and recovery time has been developed by Robiños et. al. Due to its novelty full understanding of its the mechanism and validating its performance are still lacking to utilized for application such as electronic nose. To improve reproducibility of the method a modification called pulsed galvanostatic polymerization was employed wherein removal of interdigitated electrode from the solution was eliminated such method also led to discovery that electrochemical condition or p-doping is not needed to achieve a fast response, fast recovery, and n-type gas sensor for ammonia. In another effort to improve reproducibility of the method electropolymerization via in-situ conductance monitoring was also employed, the large initial resistance of the system however prevents monitoring of percolation region. Method of production of EP gas sensor was also tested in ionic liquid and other conducting polymer such as PANI. Performance of produced sensors were assessed through various performance characteristics such as gas response, linearity, limit of detection, recovery time and sensitivity. Selected sensors were then used as chemiresistor for an electronic nose system which provided intermediate accuracy for classifying solvents. Overoxidation as a possible explanation for peculiar n-type behavior of PEDOT EP gas sensor was also proposed.