ADSORPTION AND DESORPTION OF BINARY-MIXTURES IN CONFINED GEOMETRY - APILOT POSITRON-ANNIHILATION STUDY

In confined (nanometer-scale) geometry, the effects of substrate force s and finite size produce a shift of the gas double left right arrow l iquid phase boundary from that found in corresponding bulk. The pore t ransitions also show marked hysteresis. The phase behaviour of a binar y gas mixture in confined geometry is likely to depend on the miscibil ity of the system and the interaction between the substrate and the in dividual fluid molecules/atoms. Here, we present the results of a pilo t positronium annihilation study of the condensation and evaporation o f argon-nitrogen mixtures confined in similar to 4 nm diameter cylindr ical pores in VYCOR glass.