Liquid crystalline mesophases in nanoconfinement exhibit intriguing orientational order and phase transition behaviors. Here, the plastic crystal to hexagonal columnar, and hexagonal columnar to isotropic transition temperatures are studied for the guanidinium-based ionic discotic liquid crystal confined in self- ordered nanoporous alumina membranes. The phase transition temperature of the...
The elastic properties of porous media are of great relevance in many fields of research. Previous ultrasonic measurements indicate an enhancement of the elastic moduli of adsorbates in nanoconfinement and their dependence on the Laplace pressure [1]. Simulations by Gor et al. have shown that the adsorbate’s elasticity is related to the solvation pressure, which also causes the deformation of...
Carbon capture and sequestration (CCS) involves the injection of supercritical carbon dioxide into tight rock formations such as shale. Previous studies have shown that such nanoconfinement leads to changes in phase behavior, including reduction in critical point and changes in interfacial surface tension. In this work, X-ray Raman Spectroscopy (XRS) is used to examine the structural changes...
We present an approach linking molecular Density Functional Theory (DFT) and Molecular Dynamics (MD) to the study of inhomogeneous fluids behavior in the nanoporous media. It is aimed at describing composition, volumetric and transport properties of the fluid confined within a nanopore that is connected with bulk (macropore). This problem is of interest for unconventional hydrocarbon...
While many mesoporous materials are found naturally (clays, coal, and shale), many others are synthetized for industrial applications like sensing, fluid separations, and energy storage. For the optimization of these materials for various applications, an accurate determination and understanding of the pore size distribution and morphology is vital.
Fluid phase transitions employ the...
Tight unconventional reservoirs are characterized by structural complexation and physical properties that influence the ability to recover and estimate the amount of gas in the rock. One of the physical factors is the change of the strain which may affect the gas interaction with the rocks’ surface. To study the effect of strain on the gas-surface interaction, density functional theory (DFT)...
Perturbation theory based equations of state (EOS) have the ability to provide insight on the behavior of model fluids, which makes them useful tools in thermodynamics. One of these is the Baker Henderson perturbation theory (BHPT) [1]. It uses the hard sphere fluid as a reference system, and is known to provide accurate predictions for macroscopic pure-component fluids at high temperatures....
In a context of energy transition, the growing share of gas (natural gas, hydrogen, bio-gas) in the energy mix, as well as the need to store CO2 and reduce its emissions, calls for an improvement in gas separation techniques. In this sense, free standing nanoporous graphene is a promising material because it makes it possible to exceed the selectivity to permeance ratio of other membrane...
Transport of water in soft porous materials is relevant to a broad range of applications such as ultrafiltration and reverse osmosis processes, where polymeric membranes are employed in filtration/separation, or energy related processes where proton conducting media (Nafion for instance) are used. It also pertains to important fields such as those dealing with wood/cellulosic materials, food...
The study of fluid dynamics in nanoporous materials is nowadays a topic of great interest due to the often significantly modified thermal equilibrium and non-equilibrium properties of extremely spatially confined liquids compared to their bulk counterparts. However, fluid transport in nanoscale geometries plays also an increasing role in functional materials consisting of fluid-infused solids,...
We present time-dependent macroscopic dilatometry experiments on the deformation of nanoporous monoliths (Vycor glass) upon spontaneous,capillarity-driven infiltration of water. We find two distinct dynamical regimes. One of them can be quantitatively traced to deformation originating in changes in the surface stress at the inner pore walls (dynamic Bangham's regime) upon water invasion,...
We studied experimentally spontaneous water imbibition that is triggered by capillary condensation in multiscale porous media resembling the architecture of water-conducting tissues in plants (xylem). These structures couple a nanoporous layer to arrays of microchannels of varying aspect ratio. We show that the presence of the micochannels can dramatically affect the dynamics of imbibition in...
The convective drying of a composite system made of a porous medium covered with a paste is a situation often encountered with soils, building, cultural heritage materials [1] and recently in decontamination of cementitious materials in nuclear facilities [2]. The aim of this study is to understand the convective drying behaviour of an initially saturated mortar. For simple porous systems...
The diffusion properties are a key parameter for catalysis supports. These properties are often gathered in one single parameter called tortuosity defined as the ratio of the bulk to the effective diffusivity on a given liquid or gas diffusing inside the porous media. The tortuosity parameter is expected to depend on the geometry of the porous network without chemical interaction of the...
Sparked by the interest in hydrophobic membranes for use in membrane distillation for the purification of water by means of thermally driven transport of water from impure liquid phase to a purified vapour phase, we provide the beginnings of an analytical model for the full range of transport coefficients for gas flow through porous media where the solid phase interacts with the fluid by a...
Water management is of high importance to overcome mass transport limitations in polymer electrolyte fuel cells (PEFC) at high current densities. Although the knowledge about water management in the catalyst layer is continuously increasing, it has not been fully understood so far. Within the past decade, numerous methods for ex-situ and operando imaging of water evolving in the porous...
