The sorption and permeation properties of argon were measured on a CMS membrane at different temperatures and a range of permeation pressures. The structural information of the membrane sample was derived from the analysis of adsorption isotherms at different temperatures. Further discrimination between through pores and blind pores is carried out by analyzing the permeation kinetics, from which we derive that the majority of the pore volumes are contributed by the blind pores. (C) 2009 Elsevier B.V. All rights reserved.