Temperature-induced phase transition at the polymer–water interface

Temperature-induced phase transition of polymer shows the bulk swelling change in the polymer network, which may induce the change of polymer surface properties. The contact angle measurements at the polymer–water interface were performed to observe the temperature-induced phase transition at the polymer–water interface using two-liquid technique. The dispersive and nondispersive components of surface free energy of polymer were measured above or below the phase transition temperature (lower critical solution temperature). A semi-interpenetrating polymer networks composed of sodium alginate and poly(N,N-dimethylaminoethyl methacrylate-co-ethyl acrylamide) were used as a model polymer system.