Structure and stability of hydrogen bonds under conditions of heating in nanopores

The influence of heating from 260 to 400 K on the structure and mechanism of the formation of a molecular water film adsorbed on the walls of a plane fracture with the width of 2.5 nm in a silver iodide crystal has been studied by the computer simulation method on the molecular level. The adsorption on the wall with negative ions in the surface layer strongly drops behind from the adsorption on the opposite wall with the positive ions on the surface. At the initial submonomolecular stage, the adsorbed material at temperatures close to the freezing point is a strongly clusterized two-dimensional gas containing a large amount of five-link cycles. The increase in the temperature is accompanied by a strong decrease in the degree of clusterization. Whereas the spots of the monomolecular film with clearly outlined edges are formed on the wall surface at a low temperature, under conditions of raised temperature the growth centers are absent, and the wall coating is uniform. The increase in the temperature leads to the destruction of the hexagonal structure of the film, and the strongly pronounced expressed asymmetry in the adsorption ability of opposite walls is conserved. Possible consequences of the transformations in the structure for the thermodynamic behavior of the system is discussed.