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Item type:Publication, Access status: with files , Elastocapillarity in nanopores: sorption strain from the actions of surface tension and surface stressAdsorption-induced deformation of porous materials is the generation of strains in a solid due to its interaction with adsorbing fluids. The theoretical description of adsorption-induced deformation often relies on the so-called solvation pressure, the normal component of a pressure tensor in the liquid adsorbed in the pore. Recent measurements of adsorption-induced strains in two dimensions require a description that allows for the deformation to be anisotropic. Here, we present such a description. We refrain from using the solvation pressure concept and instead base the discussion on a phenomenological description of coupled mechanics and adsorption that has well-established links to continuum mechanics. We find that our approach captures all relevant features of anisotropic sorption strain; the approach thus provides a useful alternative to the solvation pressure concept. We derive analytical expressions for the stress-strain relations in a model porous material with an array of parallel channel-like pores of high aspect ratio (length/width). These relations include separate terms from the liquid pressure, from the surface stress at the liquid-solid interface, and from a spreading tension at the solid-liquid-vapor triple line. Surface stress and liquid pressure contribute to the strains along and normal to the pore axis in a qualitatively different manner. The underlying discussion of capillary forces sheds light on the variation of the surface stress during adsorption and capillary condensation.Publicationtype: Journal ArticleScopus© Citations 24 272 322 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Adsorption-induced deformation of nanoporous materials : a reviewWhen a solid surface accommodates guest molecules, they induce noticeable stresses to the surface and cause its strain. Nanoporous materials have high surface area and, therefore, are very sensitive to this effect called adsorption-induced deformation. In recent years, there has been significant progress in both experimental and theoretical studies of this phenomenon, driven by the development of new materials as well as advanced experimental and modeling techniques. Also, adsorptioninduced deformation has been found to manifest in numerous natural and engineering processes, e.g., drying of concrete, water-actuated movement of non-living plant tissues, change of permeation of zeolite membranes, swelling of coal and shale, etc. In this review, we summarize the most recent experimental and theoretical findings on adsorption-induced deformation and present the state-of-the-art picture of thermodynamic and mechanical aspects of this phenomenon. We also reflect on the existing challenges related both to the fundamental understanding of this phenomenon and to selected applications, e.g., in sensing and actuation, and in natural gas recovery and geological CO2 sequestration.Publicationtype: Journal ArticleScopus© Citations 194 449 1088