Influence of orientational ordering transition on diffusion of carbon dioxide in carbon nanopores

Simulation studies predicted an orientational ordering transition of the mo lecular axis of supercritical CO2, inside individual graphite pores, with s ize of the order of few molecular diameters. Study of the diffusion equatio n over a real porous medium, showed significant influence of the transition on the adsorbate diffusivity. Measured permeability of CO2 adsorbed in a n anoporous carbon membrane, confirmed the simulation results by exhibiting u nusually high permeability values in the vicinity of the transition, and el ucidated the significance of the thermodynamics in the study of the kinetic properties of the adsorbed phase. (C) 2001 American Institute of Physics.