A Monte Carlo study of adsorption-induced deformation in wedge-shaped graphitic micropores

Monte Carlo simulation has been used to investigate the mechanism of deformation in wedge shaped pores and how this differs from deformation in slit-pore models. Unlike slit pores, where deformation is uniform along the axis of the pore, the deformation in a wedge pore occurs non-uniformly and the extent of deformation at one end is not the same as that at the other end. At low loadings, both ends of the pore contract because of the attraction forces between the adsorbed molecules, with a greater change at the narrow end where the adsorbate density is greater. This initial contraction results in an enhancement of the solid-fluid and fluid-fluid interactions, which compensates for the increase in the solid-solid interactions. At high loadings when adsorption has progressed toward the larger end of the pore, the two ends can either expand or contract, depending on the ratio of the adsorbate diameter to pore width.