Review—Conducting Polymers as Chemiresistive Gas Sensing Materials: A Review

Abstract

Detection of harmful gases is important to ensure human and environmental health. Industrial waste gases such as CO, NO 2 , H 2 S, and NH 3 are of typical focus among researchers over the years. Chemiresistive sensors are suitable for detecting these harmful gases. One suitable candidate material for this sensor is the conducting polymer, which offers the advantage of room-temperature operation. This review focuses on the overall development of conducting polymer as chemiresistive sensing materials. Effects of different parameters influencing sensor performance such as response, gas concentration, response time, and recovery time of conducting polymers are explored. Different conducting polymers are compared and their affinities to specific gases are determined. An understanding of pure conducting polymers assists further exploration of these polymers in composite form. A comprehensive understanding based on an overview of literature will facilitate researchers in selecting appropriate conducting polymers for different gas sensing applications and is expected to encourage further progress in this area.

Conducting polymer percolation gas sensor on a flexible substrate

“…Other PPy-based thin film and fibre sensors tend to have higher LODs than our sensor, and sub-ppm LODs are rarely achieved. 34 Three notable exceptions are reported in the studies. Yan et al 35 reported an LOD of 0.007 ppm using viral-templated gold/PPy nanopeapods, although the R 0 baseline was never recovered fully after initial exposure.…”

Hydrogen Sulfide Detection by Sensors Based on Conductive Polymers: A Review

“…As a nucleophilic (i.e., reducing) gas, H 2 S is expected to decrease the conductivity of p-type CPs and conversely increase the conductivity of n-type CPs (Wong et al, 2020). However, this classical behavior is observed only in few studies concerning polyaniline (PANI) deposited by thermal evaporation (Agbor et al, 1995), PANI doped in maleic acid with dodecyl hydrogen sulfate studied under nitrogen (Palaniappan and Saravanan, 2010), polycarbazole (Joshi et al, 2014), and polyazomethines studied in air (Patil et al, 2019).…”

“…Among the H 2 S sensors in vogue, the chemiresistive sensor is the simplest transducing system (Wong et al, 2020). Translating chemical information in an electrical signal, this device is based on a two-point contact measurement of the resistance of a sensitive material.…”

Electron Beam Induced Tailoring of Electrical Characteristics of Organic Semiconductor Films

“…Wong et al have reviewed the sensing behavior of different CPs as chemiresistive gas sensors and also explained the targeted characteristics that makes the particular CP appropriate for selected gas [198]. Hunter et al have gone over the solid state gas sensors and indicated the oxidation (or doping) plays a crucial role for CP based chemiresistive gas sensors [199].…”