Fabrication of Conductive Polymer Composite Gas Sensors by Immersion Precipitation Method

Abstract

New porous conductive polymer composites (CPCs) were fabricated based on immersion precipitation method as gas sensor sensitive layers. The conductive composite was made of poly (vinyl alcohol) (PVA) as a matrix and multiwalled carbon nanotubes (MWNTs) as conductive particles. The dense layers also fabricated for comparison. The porosity of membranes was measured by means of single point BET. The experimental results showed that by introducing the porosity, the specific surface area of nanocomposites was increased dramatically. Also, the sensing experimental results exhibited that the porosity, which was introduced to the sensitive layer by this fabrication method, improved the CPCs responses against the target vapors. The dense sensitive layers demonstrated the low-speed, low-sensitive and very noisy responses. The porous detectors showed the fast responses and the responses were increased by increasing the concentration of vapor. It can be explained on the base of more facilitation penetration of vapor molecules into the sensitive layer that could improve the swelling of polymer matrix.