Morphology dependence of surface properties of amphiphilic copolymer in various environments

Abstract

Block and random polymethylmethacrylate-poly(2-hydroxyethylmethacrylate) [PMMA-PHEMA] copolymers were prepared in order to investigate the effect of sequential archtecture on surface properties and surface and interfacial energetic components. Contact angles of various probing fluids on the polymeric surface were determined in air and alkanes (hydrophobic environment) and under water (hydrophilic environment). From contact angle data, the dispersive interaction contribution ($γ^d_s$) and the polar contribution ($γ^p_s$) to total surface free energy ($γ_s$) and interfacial energetic quantities were estimated by surface and interface physicochemical theory. Total surface energies in each environment are almost similiar for both copolymers, but both of the dispersive interaction and the polar interaction contribution are different according to the environment. These results mean that the polymer surface orient to adapt environment. In the matter of morphological effect of both polymer on surface properties, the polar interaction contribution to total energy in random copolymer is greater than that in block one for hydrophobic environment. However, for hydrophilic environment the polar interaction contribution to total energy is similar for both block and random copolymer. These facts mean that the morphological difference makes great affect on surface properties in hydrophobic environment but no significant effect in hydrophilic one.