Polyelectrolyte complex membranes – surface and permeability properties

Abstract

In order to study, how the membrane hydrophilicity influences the pervaporation (PV) separation properties in dehydration of alcohols, two polyelectrolyte complex (PELC) membranes, based on interfacial reaction of polyanionic sodium salt of sulfoethyl cellulose (SEC) with polycationic poly[dimethyl(diallyl)ammonium chloride] (pDMDAAC), or cationic surfactant benzyl(dodecyl)dimethylammonium chloride (BDDDMAC), were prepared and tested. Contact angle measurements on membrane surfaces made in various media showed that the membrane hydrophilicity, in the sense of water wettability, had not influence neither to flux nor selectivity in the PV dehydration process. On the contrary, the membrane wettability determined by contact angle measurements in the real water/alcohol separation mixture, correlated very well with the PV experiments. These findings are confronted with the solution-diffusion PV model.