Basic analysis on the origin of asymmetry potentials observed with ion-selective polymer matrix membranes

Anion-selective polymer matrix membranes with different ion-exchangers as ionophores, different plasticizers and additives were prepared in order to determine the influence of the membrane composition on the asymmetry potential and the necessary conditioning times of those membranes. The observed temperature effect on the conditioning times was interpreted according to the kinetic theory of ion-selective electrodes. Furthermore the membrane surfaces were investigated with the technique of atomic force microscopy for studying whether the asymmetry potential is caused by topographic differences between both interfaces of a membrane.