CALCULATION OF CONCENTRATION AND ELECTROSTATIC POTENTIAL PROFILES AT LIQUID-MEMBRANE WATER AND LIQUID/LIQUID INTERFACES/

A method based on statistical thermodynamics has been used to describe concentration distributions of neutral and charged molecules in the v icinity of liquid-liquid or polymer membrane-liquid interfaces. The mo del is outlined and various applications are shown. One of these is a study of the transition region at the interface of two immiscible liqu ids. The results show that this transition is not sharp. The width of the interfacial region (where the concentration varies gradually) depe nds on the mutual solubility of the two liquids and on the size of the molecules. In another application the potential drop across the inter facial region has been calculated as a function of composition of the bulk phases. This type of calculation allowed the numerical simulation of the potentiometric behavior of a recently developed ion-selective electrode which employs negatively charged ion carrier.