Adsorption and structure of Lennard-Jones model fluid in slit-like amorphous silica nanopores

Using the grand canonical Monte Carlo (GCMC) simulation technique, the effect of the heterogeneous surfaces on the confined behavior of model fluid has been studied in amorphous silica solid. The amorphous bulk silica was obtained by a melt-quench technique using molecular dynamics simulation and the heterogeneous surface was created by fracturing the bulk structure with relaxation. The adsorption isotherms. and structure properties of a Lennard-Jones model fluid in slit-like silica pores with the amorphous structure surfaces have been investigated for different pore widths and temperatures. The minimum potential distribution of the fluid-solid interaction for the amorphous surface was obtained in order to characterize the surface energy heterogeneity. The ordered surface from the P-cristobalite solid has also studied for comparison. The amorphous surface gives a stronger adsorption affinity for the probe particle due to its surface distortion structure. The different adsorption and structure behaviors in the two silica pores were compared and discussed. (C) 2006 Elsevier B.V. All rights reserved.