SAXS STUDY OF OMEGA-METAL AND ALPHA,OMEGA-METAL SULFONATO POLYSTYRENES IN TOLUENE SOLUTION

Solutions of omega- and alpha,omega-barium sulfonato polystyrenes in toluene have been investigated by SAXS as a function of concentration. A characteristic ionic peak is displayed over the whole investigated concentration range. The experimental data are in favor of the ion pair aggregation into small stable multiplets homogeneously distributed throughout the material. The characteristic distance is related to the average intermultiplet distance d. A general law has been derived for the dependence of d on molecular weight, functionality, and concentration of the polymer. The size of the multiplets does not depend significantly on polymer concentration and molecular weight. Below a critical concentration which depends on the chain length, solutions of difunctional samples display a constant average intermultiplet distance. This behavior has been attributed to the partial multiplet dissociation by the fully extended chains. Sample preparation and subsequent thermal treatment have no influence on the position of the ionic peak but can affect the intensity of the peak and the upturn in scattered intensity at very small angles.