KINETICS OF DICHLOROMETHANE ABSORPTION INTO THE CONDUCTIVE POLYMERS POLY(N-METHYLPYRROLE) AND POLY(N-METHYLPYRROLE/POLYSTYRENESULFONATE)

Mass transients have been measured for the sorption of dichloromethane from aqueous/electrolyte solution into the organic conductive polymers poly(N-methylpyrrole-ClO4) and poly(N-methylpyrrole-polystyrene-sulfonate). The data are analysed within the context of two sorption models: pseudo-first-order kinetics for single-site adsorption and diffusion-limited absorption in an infinite plane sheet. Rate constants and apparent diffusion coefficients for absorption differ by a factor of 2 for oxidized and reduced poly(N-methylpyrrole-ClO4) but are very similar for the two oxidation forms of poly(N-methylpyrrole-polystyrenesulfonate). These observations; are discussed in terms of the relative hydrophobicities of the oxidized and reduced forms of each polymer. A detailed study of the sorption rate constant vs film thickness reveals information on the rate-limiting step in the absorption process.