WIDE-BAND DIELECTRIC-SPECTROSCOPY OF HYDRATED POLY(HYDROXYETHYL METHACRYLATE)

This paper examines the role of water in hydrated poly(2-hydroxyethyl methacrylate) (PHEMA). Dielectric complex permittivity measurements ar e reported over an extended range of frequency (0.1 Hz-1 GHz) and temp erature (77-353 K) with water content as a disposable parameter. Data are correlated with the results of earlier relaxation experiments, not ably nuclear magnetic resonance, to provide insight into water-polymer interactions at the molecular level. Three relaxations are detected i n the dry polymer, whereas, in the hydrated system, a fourth relaxatio n is identified and attributed to a low-temperature phase transition o f the water itself. Relaxation processes of the host polymer are stron gly influenced by the presence of water.