POSITRON AND POSITRONIUM ANNIHILATION STUDIES OF PHASE-BEHAVIOR IN CONFINED GEOMETRY

In this paper we present a brief review of the current state of positr on annihilation research into the phase behaviour of fluids confined w ithin restricted boundaries. We summarise, in the form of selected exa mples, the work done so far on: (1) fluids confined in the nanometer-s ize pores of VYCOR glass, with particular emphasis on the confined pha se diagram and the mechanisms behind phase transitions compared to bul k. (2) The adsorption/physisorption of gases on internal surfaces of g rafoil and the potential of positron technique for revealing physical properties, such as the intricate molecular arrangements during phase transitions of the ''layered'' fluid.