Surface properties of polymer hydrogels

Abstract

The characterization of polymer-water interfaces by contact angle measurement is performed using waterimmiscible liquids. It gives the dispersive and the nondispersive components of surface tension as a function of functional group of copolymer hydrogels. Using the method of Rusanov, the contact-angle-induced deformation of the three-phase region in our systems was examined. The systems used were poly(2-hydroxyethyl methacrylate)(HEMA) and related copolymers. Contact angle measurements on polymer hydrogels were performed at various temperatures. and we obtained the dispersive and the nondispersive components of the surface tension of polymer hydrogel at each temperature. Utilizing the temperature dependence values, we obtained the surface entropies of polymer hydrogels. The systems used were isotactic and syndiotactic poly(HEMA) and related copolymers. The contact angles were also measured by using droplets of water-immiscible liquids under conditions in which the polymer hydrogel was fully hydrated. Finally, we performed a series of contact angle measurement on polymer-water interface at various pH conditions on polymer-water interface at various pH conditions of water. The data were analyzed and we obtained the pH dependence of the dispersive and nondispersive components of surface tension. The polymer hydrogels used were three copolymers containing HEMA monomer.