Dispersion transition and the nonergodicity of the disordered nanoporous medium-nonwetting liquid system
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TICAL, NONLINEAR, AND SOFT MATTER PHYSICS
Dispersion Transition and the Nonergodicity of the Disordered Nanoporous Medium–Nonwetting Liquid System V. D. Borman*, A. A. Belogorlov, V. A. Byrkin, V. N. Tronin, and V. I. Troyan National Research Nuclear University MEPhI, Kashirskoe sh. 31, Moscow, 114509 Russia *email: [email protected] Received May 28, 2013
Abstract—The experiments in which a nonwetting liquid does not flow from a disordered nanoporous medium are described. The outflow is shown to depend on the degree of filling of the porous medium and its temperature in a critical manner. A physical mechanism is proposed where the transition of a system of liquid nanoclusters in a confinement into a metastable state in narrow filling and temperature ranges results from the appearance of a potential barrier due to the fluctuations of the collective “multiparticle” interaction of liquid nanoclusters in neighboring pores of different sizes at the shell of a percolation cluster of filled pores. The energy of a metastable state forms a potential relief with numerous maxima and minima in the space of a porous medium. The dispersed liquid volume in a metastable state is calculated with an analytical percola tion theory for a ground state with an infinite percolation cluster. The outflow time distribution function of pores is calculated, and a power law is obtained for the decrease in nonwetting liquid volume retained in a porous medium with increasing time. The relaxation of the system under study is a multistage process accom panied by discontinuous equilibrium and overcoming of numerous local maxima of a potential relief. The for mation of the metastable state of retained nonwetting liquid results from the nonergodicity properties of a dis ordered porous medium. The proposed model can describe the detected dependences of dispersed liquid vol ume on the degree of filling and temperature. DOI: 10.1134/S1063776113140094
1. INTRODUCTION When filling the space of nanopores in a nanopo rous medium, a liquid is dispersed and transforms into an ensemble of nanoclusters. The physical and chem ical properties of such ensembles in a confinement are of interest for various technologies under development [1–12]. The filling of a nanoporous medium with a nonwetting liquid, e.g., mercury or water, at excess pressure is applied to characterize the porous medium, in particular, to determine the specific volume of pores, the specific surface area, and the pore size dis tribution [13, 14]. For a description, researchers use various models of both a porous medium and the pro cess of infiltration–defiltration [15–24]. When flow ing from a nanoporous medium, part of the nonwet ting liquid transforms into a dispersed “wetting” state and is retained in the disordered medium. Nonwetting liquid can exist in this state for days and months [11, 12]. According to the concepts introduced in the phys ics of magnetic (glassy) disordered systems [25, 26], a disordered nanoporous medium with a nonwetting liquid can be considered as nonergo
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