Sorption and interactions of gases in polyaniline powders of different doping levels

Abstract

AbstractSorption of different gases (N2, O2, CH4, and CO2) were performed on as‐synthesized polyemeraldine base, on HCl 4M doped, on NH4OH 1M undoped, and on HCl 10−2M redoped powders. In the pressure range examined (100–700 torr), linear sorption isotherms were observed for N2 and correspond to an ordinary dissolution in Henry's law state. Concerning O2, CH4, and CO2, nonlinear isotherms were evidenced and could be described by the dualmode sorption mechanism proposed for glassy polymers, which consists of the combination of a Henry's type dissolution with a Langmuir sorption in unrelaxed gaps between macromolecular chains. Specific interactions between polyaniline (PANi) and O2, CH4, and CO2, were studied. Gas permeation experiments were performed by using different upstream pressures, P1, and have confirmed the dissolution of Henry's type for N2 and the dualmode mechanism for O2 and CO2. From the fits of the sorption isotherms, gas solubilities of N2, O2, CH4, and CO2 were calculated for three different gas pressures and analyzed in terms of gas separation for permeation experiments. © 1995 John Wiley & Sons, Inc.