Effects of hydrophilic/hydrophobic surfaces on polymer-complexation kinetics

To establish hydrophilic/hydrophobic effects on polymer-complexation kinetics, chitosan resins were prepared by radical copolymerization of methacryloyl-modified chitosans with 2-hydroxyethyl methacrylate and/or styrene monomers. The primary particles of the gelled copolymers in the suspensions were nicely solidified by basic coagulation bath to form globular beads. Degree of the hydrophilic/hydrophobic properties was controlled by the copolymerization ratio, and each ion-adsorption kinetics was evaluated by batch method. The initial rate of adsorption in hydrophilic chitosans was higher than that in hydrophobic chitosans, which was attributed to less thickness of the boundary film. We quantitatively evaluated the rate-determining steps by the initial-rate analysis, in which the viscosity of the suspension contributes to the film-diffusion kinetic resistance. The role of hydrophilic/hydrophobic properties of the resins is reasonably rationalized to the length of the boundary films by considering long-range interactions between the ion and surface. Our results are robust evidence for the ion-surface interactions. (c) 2018 Wiley Periodicals, Inc.