INTERACTIONS OF NEUTRAL ORGANICS IN AQUEOUS-SOLUTION WITH CONDUCTING POLYMER-FILMS OF POLY(N-METHYLPYRROLE) AND POLY(N-METHYLPYRROLE POLYSTYRENESULFONATE)

We have investigated the interactions between halocarbons in aqueous solution and conducting polymer films of poly(N-methylpyrrole) (PNMP) and poly(N-methylpyrrole/polystyrenesulfonate) (PNMP/PSS) employing cyclic voltammetry, UV-visible spectroelectrochemistry, and electrochemical quartz crystal microgravimetry (EQCM). The absorption of dichloromethane (DCM) into both films is adequately described by the Langmuir isotherm model for monolayer sorption. The partitioning of DCM from the aqueous phase into reduced PNMP is up to 2.5 times greater than the partitioning into the oxidized form of the polymer. The amount of DCM absorbed by both redox forms of the PNMP/PSS composite film is, however, identical. These observations are discussed in terms of the changes (or lack thereof) in chemical, physical, and morphological properties that accompany the redox processes of these films. Spectroscopic measurements suggest that there is slight chemical interaction between DCM and reduced PNMP and PNMP/PSS, but there is much less interaction with the oxidized polymers.