Development of PEDOT-PSS/Zeolite composite as a Gas Sensor

Abstract

Composites with Poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid), PEDOT-PSS, as the matrix containing zeolites of various Si/Al ratios in the range of 23-280 were fabricated to investigate the effect of Si/Al ratios on electrical conductivity sensitivity responses towards the target gas. The electrical conductivity responses of PEDOT-PSS/Zeolite composites were altered due to the available adsorption sites for gas molecules. The addition of zeolites to the pristine PEDOT-PSS improves the electrical conductivity sensitivity of the composites by enhancing the interaction between PEDOT-PSS and target gas. Composites with PEDOT-PSS matrix containing faujasite zeolites type Y were fabricated to investigate the effects of cation type of faujasite zeolite type Y on the electrical conductivity response when exposed to the target gas. The types of cation in zeolite Y micropores can tuning adsorption-desorption properties of zeolite Y, which influence the electrical sensitivity of the composite. Responses and the interaction mechanism of conductive polymer/zeolite composites sensor were investigated. The results obtained can be attributed to the electronegativity of the transition metal cations exchanged into the zeolite Y micropores, which critically affects the adsorption properties of the zeolite Y, and which in turn influences the electrical sensitivity of the composites. The effect of metal exchanged zeolite Y cover layer and the thickness of cover layers on electrical conductivity response of PEDOT-PSS and their sulfur dioxide sensing properties have been investigated. Their gas sensing response; sensitivity, response time, recovering time and complication of fabrication were compared with PEDOT-PSS/MY zeolite composites in powder mixing compress form.