Interaction between poly(styrene sulfonate) and dodecylpyridinium chloridein ethanol-water mixed solvents

Binding of dodecylpyridinium chloride to poly(styrene sulfonate) in ethanol -water mixed solvent was measured by a surfactant-selective electrode which consists of polymeric materials only and thus shows a good electrode perfo rmance even in mixed solvent. It was found that both intrinsic binding and the cooperative effect were reduced by added ethanol. This is ascribed to r eplacement of water molecules hydrophobically hydrated around the hydrophob ic moieties of the polymer and the surfactant with ethanol molecules. This tendency is correlated with the free energy change of a surfactant molecule when transferred from water to an ethanol-water mixed solvent, which was a lso measured by the same surfactant electrode as used in the binding study. (C) 1999 Elsevier Science B.V. All rights reserved.