Poly (vinyl methyl ether) hydrogel formed by high energy irradiation

Abstract

Poly(vinyl methyl ether) shows a lower critical solution temperature behavior in water. The dimension of the polymer molecules depends on the temperature. A thermo-sensitive hydrogel was synthesized by irradiation of an aqueous solution of poly(vinyl methyl ether) with electron beam and γ-rays. At high polymer concentration a bulk gel was formed. The structure of the gel in the dry, swollen and shrunken state was investigated by field emission scanning electron microscopy (FESEM). It could be shown, that the gel synthesized by electron beam has a sponge-like structure consisting of cavities (≈ 1 μm) separated from each other by a polymer layer full of holes (≈ 10 nm). The macroscopic gel is characterized by several techniques, e.g. determination of the Mc-value by NMR-relaxation measurements.