Water at Biological Interfaces - Structural and Functional Aspects

Abstract

Abstract The structure of water near interfaces is reviewed in this paper and evidence presented for the existence of notable changes in the properties of such vicinal water. The depth of the changed surface zone is discussed; it appears that this depth may approach a tenth ofa micron. Possible types of vicinal water structures include the high-pressure ice polymorphs and clathrate. cage-like entities. Some examples of thermal anomalies in the properties of vicinal water are reviewed: at least four different thermal anomalies occur between the freezing and boiling point. It is concluded that thex anomalies likely reflect higher order phase transitions in the structured units of the vicinal water. These transitions appear not to be notably affected by the detailed chemical nature of thc solid substrates with which thc ater is in contact. This is referred to as the “paradoxical effect” and is tentatively interpreted in terms of an energy delocalization phenomenon. The vicinal water structures near solid int...