Spontaneous outflow efficiency of confined liquid in hydrophobic nanopores

The suspension of nanoporous particles in a nonwetting liquid provides a unique solution to the crux of superfluid, sensing, and energy conversion, yet is challenged by the incomplete outflow of intruded liquid out of nanopores for the system reusability. We report that a continuous and spontaneous liquid outflow from hydrophobic nanopores with high and stable efficiency can be achieved by regulating the confinement of solid–liquid interactions with functionalized nanopores or/and liquids. Full-scale molecular-dynamics simulations reveal that the grafted silyl chains on nanopore wall surfaces will promote the hydrophobic confinement of liquid molecules and facilitate the molecular outflow; by contrast, the introduction of ions in the liquid weakens the hydrophobic confinement and congests the molecular outflow. Both one-step and multistep well-designed quasistatic compression experiments on a series of nanopores/nonwetting liquid material systems have been performed, and the results confirm the outflow mechanism in remarkable agreement with simulations. This study offers a fundamental understanding of the outflow of confined liquid from hydrophobic nanopores, potentially useful for devising emerging nanoporous-liquid functional systems with reliable and robust reusability.

The self-consistent model of the anomalously slow relaxation of the systems nonwetting liquid–nanoporous medium

This paper provides information on a self-consistent model of an anomalously slow relaxation of nonwetting liquid–nanoporous medium systems with a random size distribution of pores, which introduces changes in interaction between local liquid cluster configurations in the process of liquid outflow from the porous medium. A self-consistent equation was deduced, the solution of which determines a functional connection of porous medium filling degree or time [Formula: see text]. It is shown that the anomalously slow relaxation is presented as a process of decay of interacting local metastable configurations, initialized by thermal fluctuations. As time increments, relaxation acceleration takes place with subsequent avalanche fluid outflow from the porous medium, which is connected with interaction decrease between local configurations. The dependence of the fraction of volume of liquid remaining in a porous medium changes by the power law [Formula: see text]. It is shown that for a system of water–L23 at the initial stage in the time range of [Formula: see text], an index assumes a constant value [Formula: see text], while at the following stage the acceleration of relaxation and the increase of parameter [Formula: see text] are observed.

States of a dispersed nonwetting liquid in a disordered nanoporous medium

Three different states of a dispersed nonwetting liquid (water) in the Fluka 100 C8 and Fluka 100 C18 disordered porous media, as well as transitions between these states under variation of the temperature and the degree of filling, have been revealed. It has been shown that the appearance of such states is due to the broadening of the pore size distribution function f(R), fluctuations of configurations of neighbors in the system of pores and fluctuations in the configuration of a pore and its environment consisting of filled and empty pores in the percolation cluster. These states and transitions are caused by the competition between the effective repulsion of the nonwetting liquid from the wall of the pore, which is responsible for the "extrusion" of the liquid from the pore, and the effective collective "multiparticle" attraction of the liquid cluster in the pore to clusters in the neighboring connected pores. The observed difference in the behavior of the Fluka 100 C8/water and Fluka 100 C18/water systems and the previously studied Libersorb-23 (L23)/water system indicates a significant dependence of the state of these systems on the type of disorder in them.