INFLUENCE OF ADDITIVES ON ELECTRICAL CHARACTERISTICS OF ION-SELECTIVE POLYMERIC MEMBRANES

New ion-selective membranes based on polyimide polymeric matrix with synthetic ionophores to be used to obtain potentiometric ion sensor were characterized in terms of electrical parameters. Polyimide based polymeric membranes were characterized as regards the a.c. impedance and electrochemical analyses. The experiments put in evidence the influence of the membrane composition on the electrochemical answer of the sensor. It was concluded that the addition of the lipophilic agent in the selective membrane composition results in membranes with higher dielectric constant. The dielectric constant of the polymeric matrix of the ion-selective devices based on neutral carriers presents an important influence on selectivity.