ON MESOSCOPIC WATER DROPLETS DISPERSED IN BUTYL RUBBER

Water dispersed in butyl rubber containing hydrophilic components has been studied with differential scanning calorimetry, dielectric spectroscopy in the frequency range from 5 Hz to 10 GHz, thermally stimulated depolarisation currents, and small angle X-ray measurements. Hydrophilic components in the rubber matrix act as adsorption sites for water molecules. Two populations of water droplets with radii of the order of magnitude of 2 nm are formed. In the mesoscopic hydrophobic confinement the dielectric relaxation of the liquid water droplets is shifted to higher frequencies compared with bulk water. The relaxation of water in the frozen droplets is slower compared to that of bulk ice. Neither molecular water nor clusters of bulk water are found in the rubber.