Diffusion and capillary flow in track-etched membranes

Nitrogen transport at 77 K through the cylindrical pores in 0.01 mum track- etched membranes occurs by a combination of Knudsen diffusion and capillary flow. This transport can be quantitatively predicted without adjustable pa rameters from a modified form of the theory of Abeles et al. (1991). This i mplies that some anomalies previously observed for transport with capillary condensation are geometrical artifacts of the ht heterogeneous pores which were used. (C) 2001 Elsevier Science B.V. All rights reserved.