Evaluation and selection of sensing materials for carbon dioxide (CO2) sensor by molecular modeling

Abstract

We report a molecular modeling study to evaluate and select conducting polymers (CPs) for use as the sensing layer for carbon dioxide (CO2) sensor. The interactions between gases and sensing materials and the adsorptions of small gas molecules on polymer sensing films are described and investigated. Polymers considered for this work include emeraldine base polyaniline (EB-PANI) and unprotonated sodium polyaniline salt (NaSPANI) with sulfur to nitrogen ration (S/N) of 0.4, 0.5 and 0.6 Gases studied include CO2, humidity (H2O). Comparative studies of NaSPANI and PANI show differences on the polymer-gas interaction energy and gas sorption number because of the -So3NA groups on the phenyl rings.