Multilayer adsorption on solid surfaces: Calculation of layer thickness onthe basis of the athermal parallel layer model

A method for calculating the dependence of equivalent layer thickness on bu lk phase composition in athermal binary mixtures has been devised. The prer equisite to the procedure is knowledge of the adsorption excess isotherm an d of the cross-sectional area of one component. After integration of the ex cess isotherm according to the Gibbs equation, the equations of the paralle l layer model are used to calculate the composition of the monolayer in con tact with the surface, which in turn is used to calculate the thickness of the adsorption layer. The proposed method was tested on a hypothetical expe rimental system with calculated excess isotherms and a known function of eq uivalent layer thickness. Reliable results were obtained, especially when a dsorption was preferential, the surface was relatively homogeneous, and the ratio of the cross-sectional areas of the individual components was close to the ratio of molar fractions. (C) 2001 Academic Press.