ELECTROCHEMICAL-BEHAVIOR OF POLYELECTROLYTE COMPLEX MEMBRANES

Oriented concentration potentials and DC resistances of Symplex polyelectrolyte membranes made of cellulose sulfate (CS) as a polyanion and of poly(dimethyldiallylammonium chloride) (PDMDAAC) or benzyl-[2-(dodecylcarbamoyl)ethyl]dimethylammonium chloride (Quartolan) as counter-cations were measured and correlated to dialysis permeability coefficients. Concentration potentials showed that the preparation method used leads to membranes with an excess of the charge of one component. Cationic symmetrical PDMDAAC/CS membranes, anionic asymmetrical Quartolan/CS membranes and anionic asymmetrical combination of both types have the fixed ion molarity 0.05, 0.005 and 0.001 mol per litre of imbibed liquid, respectively. Specific resistances are 10(4) OMEGA cm in 0.005M- and 0.01M-KCl, 10(3) OMEGA cm in 0.05M-KCl and even higher in combined membranes. Areal resistances are low due to small membrane thickness. A linear correlation between DC conductivity and permeability has been found. Thus, also Symplex polyelectrolyte membranes can be tested by electrochemical methods.