A computer simulation study of stick-slip transitions in water films confined between model hydrophilic surfaces. 1. Monolayer films.
The shear behavior of monolayer water films confined in a slit-like pore between hydrophilic walls is simulated in the quasistatic regime using the grand canonical Monte Carlo technique. Each wall is represented as a hexagonal lattice of force sites that interact with water through an orientation-dependent hydrogen-bonding potential. When the walls are in registry, the water oxygen atoms form either a crystal- or fluid-like structure, depending on the period of the wall's lattice. In both cases, however, the monolayer structure is orientationally disordered. Both the crystal- and fluid-like monolayers prove to be capable of experiencing well-defined stick-slip transitions, with the largest yield stress occurring in the crystal-like case. Beyond the yield point, the crystal-like monolayers "melt", but their structure and molecular motion differ in many respects from those characteristic of normal fluids.
Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.
Alexander
A
Pertsin
Michael
M
Grunze
D003198:Computer Simulation; D003460:Crystallization; D006860:Hydrogen Bonding; D046911:Macromolecular Substances / Q000737:chemistry*; D008566:Membranes / Q000737:chemistry*; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry; D033081:Shear Strength; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D046911:Macromolecular Substances; D014867:Water; D010100:Oxygen