Enthalpies of dilution of some polycation solutions and exchange enthalpies of polycation counterions

Abstract

AbstractExperimental data of the enthalpies of dilution of aqueous polycation solutions with water and with salt solutions are presented, as well as the exchange enthalpies of polycation counterions. Measurements were performed using a titration calorimeter. The procedure of obtaining the exchange enthalpies from the calorimetric data is described. The knowledge of these exchange enthalpies reveals information about the enthalpies of formation of (polycation‐polyanion) complexes which are the basic material for the preparation of so‐called “symplex” membranes employed in pervaporation. The data obtained are also of interest for paper manufacturing industries because of the interaction energies of polyelectrolytes with multiple‐charged electrolytes, e. g. lignin sulfonate. The experimental enthalpies of dilution and exchange enthalpies determined for the different counterions are discussed and can be explained by differences in molecular conformation and by different binding of the counterions, respectively.