COOPERATIVE ADSORPTION OF NETWORK FORMING FLUIDS ONTO CRYSTALLINE SURFACES - STRUCTURE AND CONNECTIVITY OF THE INTERFACE

Density profiles and first layer adsorption isotherms of a network for ming fluid near a crystalline surface are investigated using the Percu s-Yevick approximation for the associative Henderson-Abraham-Barker (H AB) equation. The fluid molecule is represented as a hard sphere with four independent attractive sites. The surface is described as a hard wall with a lattice of adsorbing sires. It is shown that the associati on induces a new type of cooperativity related to a bridging between t he adsorbing sites due to tree-like clusters adsorption, The density p rofiles calculated exhibit reasonably good agreement with the Monte Ca rlo computer simulation data. The connectivity properties of the inter face are studied and an interfacial percolation threshold is predicted to exist. The mean thickness tau of the adsorbed layer and the connec tedness wall-particle correlation functions are calculated via the con nectivity analogue of the HAB equation. It is shown that the adlayer m ay become infinitely thick with the mean cluster size S in the bulk be ing finite. (C) 1997 American Institute of Physics.