Multiscale Nature of Poromechanics of Nanoporous Adsorbents
Deformation of nanoporous materials in the process of gas adsorption is currently actively explored with respect to the design of novel flexible adsorbents and membranes for hydrocarbon separation, actuators, nanobumpers, energy storage devices, as well as enhanced gas recovery and carbon dioxide sequestration in coal seams and shales. The key question is how adsorption in nanopores affects material deformation and adsorbate transport on the macroscopic level and, vice versa, how the alteration of nanoporosity due to matrix deformation under confining stress affects the sorption capacity and selectivity. This topic represents a fundamental interdisciplinary problem, solution of which requires incorporation of the methods of classical poromechanics, widely used in geoscience for measuring and modeling coupled fluid flow and deformation in macroscopic porous media, into adsorption thermodynamics and molecular simulations of adsorption equilibrium on the nanoscale level. I will present a unified theoretical approach that extends the Gibbs adsorption thermodynamics to poroelastic nanomaterials. Special attention is paid to the interpretation of the strain measurements by in situ SAXS/SANS and dilatometry, in particular the adsorption deformation effects on the scales of micro- (<2 nm) and meso- (2 – 50 nm) pores. Examples include carbons, coal, silicas, MOFs, and zeolites.
Neimark, Reconciliation of Gibbs Excess Adsorption Thermodynamics and Poromechanics of Nanoporous Materials, Poromechanics VI, 2017, p. 56-63
Balzer et al, Adsorption-Induced Deformation of Hierarchically Structured Mesoporous Silica – Effect of Pore-Level Anisotropy, Langmuir, 2017, V.33, p.5592
Balzer et al, Mechanical Characterization of Hierarchical Structured Porous Silica by in-situ Dilatometry Measurements during Gas Adsorption, Langmuir, 2019, V.35, p.2948
Ludescher et al, In-situ small-angle neutron scattering investigation of adsorption-induced deformation in silica with hierarchical porosity, Langmuir, 2019, V.35, P. 11590
Neimark and Grenev, Adsorption-Induced Deformation of Microporous Solids: a New Insight from a Century Old Theory, Journal of Physical Chemistry C, 2020, 124, 749.
Corrente et al, Deformation of Nanoporous Materials in the Process of Binary Adsorption: Methane Displacement by Carbon Dioxide from Coal, J. Physical Chemistry C, 2021, V.125, P. 21310.
Short bio :
Dr. Alexander V. Neimark is a Distinguished Professor of Chemical and Biochemical Engineering at Rutgers University. He received his doctor of science degree at the Moscow State University, and then worked at the Institute of Physical Chemistry of Russian Academy of Sciences. Prior to joining Rutgers in 2006, he held visiting positions at Mainz University (Germany), CNRS (France), and Yale University (USA) and then served as Research Director of the Textile Research Institute TRI/Princeton in 1996-2006. He is a recipient of a number of national and international awards and honored appointments, including Guggenheim Fellow, Blaise Pascal International Chair, Humboldt Fellow, Fellow of American Institute of Chemical Engineers, and Distinguished Visiting Fellow of the Royal Academy of Engineering. Dr. Neimark research interests include thermodynamics, statistical mechanics, molecular modeling, design and characterization of nanoporous solids and self-assembled soft materials. He published 280+ scientific papers, named a highly cited scientist by ICI, citation index h=71.