Investigation of the percolation transition in a nonwetting liquid-nanoporous medium system

The flows of liquid into and out of a nanoporous medium are studied as proc esses leading to the fluctuation formation and the growth of fractal cluste rs of filled and empty pores, respectively. The conditions for stable growt h of such fluctuations are analyzed as a function of the interfacial energy between the liquid and the porous medium and the surface energy of the liq uid. Expressions are obtained for the pressure at which the barrier for flu ctuation filling and emptying of the pores vanishes. In general, it is show n for porous media with a pore-size distribution that these processes can b e interpreted as a percolation phase transition. The volume and susceptibil ity of a liquid-porous medium system near the transition points with inflow and outflow of the liquid are calculated. The phenomenon of nonoutflow of a nonwetting liquid from a porous medium and hysteresis of the flow of liqu id into and out of a porous medium are explained on the basis of the mechan ism considered. The results of an experimental investigation of these proce sses in the system liquid Wood's alloy-silochrome 80 and silochrome 120 are presented. The experimental data obtained can be described on the basis of the proposed mechanism. (C) 2000 MAIK "Nauka/Interperiodica".