ADSORPTION OF POLYMER MIXTURES FROM DILUTE AND SEMIDILUTE SOLUTIONS

The adsorption of mixtures of thermodynamically compatible and incompatible polymer pairs from a common solvent has been studied in the concentration range of dilute and semidilute solutions. The critical concentration of overlap (crossover region) was dependent on the component ratio estimated from the relationship [η]AB = [η]Aφ(symbol)A + [η]Bφ(symbol)B, where [η]i is the intrinsic viscosity of pure components in common solvent, φ(symbol)A and φ(symbol)B are their volume fractions in the mixture, and [φ(symbol)]AB is the average intrinsic viscosity of the mixture. It was found that the processes of macromolecular aggregation proceed by transition from the dilute to the semidilute regime and that during adsorption macromolecular aggregates pass onto the adsorbent surface. This transition diminishes in the crossover region. Considering the solution of polymer mixture A + B as a solution of A in mixed solvent (solvent + B) and vice versa, the peculiarities of adsorption are discussed, which are connected with the changing thermodynamic quality of mixed solvent. © 1993 Academic Press. All rights reserved.