THE INTERACTION BETWEEN OPPOSITELY CHARGED POLYELECTROLYTES IN THE PRESENCE OF SOLID-SURFACES

The interaction between the oppositely charged polyelectrolytes poly(d imethyldiallylammonium chloride) (PDMDAAC) and poly(maleic acid-co-alp ha-methylstyrene) (P(MS-alpha-MeSty)) in the presence of inorganic fin e particles such as clay, silicic acid and glass pearls has been inves tigated. In experiments involving only adsorption of PDMDAAC the drivi ng forces are electrostatic attractions between the anionic particles and the polycation. The amount of adsorbed PDMDAAC necessary for chang ing the surface charge of the substrates from negative to positive inc reased with increasing specific surface area. The adsorption of PDMDAA C and P(MS-alpha-MeSty) from their mixed solutions on to the inorganic fine particles showed a synergistic effect with respect to the amount of cationic surface charge. This effect increased with the surface ch arge density of the solid particles. The interaction of P(MS-alpha-MeS ty) with preadsorbed PDMDAAC led to a change in the polarity of the mo dified particles and did not show a synergistic effect. The obvious di fference between the adsorption from the mixed solutions and sequentia l adsorption is discussed in terms of the configuration of adsorbed po lyelectrolyte complex particles formed in the solution or at the solid /liquid interface.