Oversolubility arises when the gas solubility in a nanoconfined liquid is larger than in the bulk liquid (the latter usually follows Henry’s law stating that the concentration of solubilized gas is proportional to the gas pressure above the liquid).1,2 Oversolubility is expected to drastically modify the confinement and transport properties in nanoporous materials with potential beneficial or detrimental effects for adsorption, separation and catalysis as well as long-term storage applications relying on natural media as efficient diffusion barriers. Here, we report an experimental and molecular simulation study on the effect of oversolubility on confinement and transport in nanoporous materials. In a first part, considering different gases (e.g. CO2, CH4, H2), we will identify the different mechanisms that are responsible for oversolubility:2 (1) adsorption-driven phenomena that arises from the strong interaction between the gas molecules and the pore surface versus (2) confinement-induced enhanced solubility in which solubility is favored in the regions of low solvent density formed by the layering of the solvent. In a second part, as a striking example of oversolubility effects in nanoconfinement, we will show how the thermodynamics of the triple line formed by a water capillary bridge confined between two flat surfaces is affected in the presence of carbon dioxide.3 In more detail, by means of atom-scale simulations, we found that carbon dioxide accumulates at the solid walls and, preferably, at the triple lines where it plays the role of a line active agent: gas accumulation at the lines decreases the negative line tension while water depletion from the lines has the opposite effect.

Oversolubility in nanoconfinement: From adsorption in porous media to wetting of interfaces

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.