THEORETICAL PROGRESS IN POLYMER ADSORPTION, STERIC STABILIZATION AND FLOCCULATION

The range of validity of scaling and mean field models for polymers at interfaces is discussed. According to a recent analysis by D. W. Schaefer, mean field theories describe the properties of polymers in solution correctly over a wider range of concentration and solvency than does scaling. Only for flexible polymers in very good solvents at concentrations below a few percent are scaling methods preferred. In polymer adsorption, high segment densities occur and therefore mean field theories are more appropriate than scaling. The most detailed mean field theory for polymers at interfaces has been proposed by J. M. H. M. Scheutjens and G. J. Fleer. The distribution of segments as a function of ranking number and, consequently, end effects (tails) are taken fully into account.