INTERFACIAL MELTING OF ICE IN GRAPHITE AND TALC POWDERS

Quasi-elastic neutron scattering of H2O-saturated powders of graphitized carbon black and talc show unfrozen water persisting below the bulk freezing point, to temperatures below -30-degrees-C. Several features are consistent with surface melting at the ice-substrate interfaces, but the temperature dependence disagrees with the standard theory. The discrepancies are attributed to size effects, and are supported by model calculations. Similarities with the behavior of unfrozen water in subzero soils suggest that they share the same fundamental mechanisms.