TY - JOUR
T1 - Modeling structural flexibility in 3D carbon models
T2 - A hybrid MC/MD approach to adsorption-induced deformation
AU - Corrente, Nicholas J.
AU - Parashar, Shivam
AU - Gough, Raleigh
AU - Hinks, Elizabeth L.
AU - Ravikovitch, Peter I.
AU - Neimark, Alexander V.
N1 - Publisher Copyright:
© 2025 The Authors
PY - 2025/5/5
Y1 - 2025/5/5
N2 - Predicting adsorption-induced deformation in nanoporous carbons is crucial for applications ranging from gas separations and energy storage to carbon capture and enhanced natural gas recovery, where structural changes can significantly impact material performance and process efficiency. The interplay between adsorption and material deformation presents both challenges and opportunities, particularly for CO2–CH4 displacement processes in geological structures where matrix swelling can alter reservoir permeability. We investigate adsorption-induced deformation of nanoporous carbons using an original hybrid Monte Carlo/Molecular Dynamics (MC/MD) simulation approach that couples adsorption sampling with structural relaxation. By studying CH4 and CO2 adsorption on 3D carbon structures of varying densities (0.5–1.0 g/cm3), we demonstrate characteristic non-monotonic deformation behavior, with initial contraction at low pressures followed by expansion at higher pressures. A key contribution is the direct calculation of isothermal compressibility of adsorbate saturated porous structures from the volume fluctuations during NPT-MD simulations, which reveals dramatic mechanical property changes during adsorption. In the process of adsorption, carbon structures exhibit initial softening followed by substantial hardening, with a dramatic increase of the volumetric modulus in denser carbons. Using elastic theory relationships, we estimate the adsorption stresses reaching 175 MPa, that provides crucial insights into potential material degradation mechanisms. For binary CH4/CO2 mixtures, increasing CO2 content amplifies both contraction and expansion effects due to stronger fluid-wall interactions. The iterative MC/MD methodology enables direct observation of the structural evolution and quantitative estimates of the mechanical properties, which are difficult to measure experimentally, advancing our understanding of coupled adsorption-deformation processes in nanoporous materials.
AB - Predicting adsorption-induced deformation in nanoporous carbons is crucial for applications ranging from gas separations and energy storage to carbon capture and enhanced natural gas recovery, where structural changes can significantly impact material performance and process efficiency. The interplay between adsorption and material deformation presents both challenges and opportunities, particularly for CO2–CH4 displacement processes in geological structures where matrix swelling can alter reservoir permeability. We investigate adsorption-induced deformation of nanoporous carbons using an original hybrid Monte Carlo/Molecular Dynamics (MC/MD) simulation approach that couples adsorption sampling with structural relaxation. By studying CH4 and CO2 adsorption on 3D carbon structures of varying densities (0.5–1.0 g/cm3), we demonstrate characteristic non-monotonic deformation behavior, with initial contraction at low pressures followed by expansion at higher pressures. A key contribution is the direct calculation of isothermal compressibility of adsorbate saturated porous structures from the volume fluctuations during NPT-MD simulations, which reveals dramatic mechanical property changes during adsorption. In the process of adsorption, carbon structures exhibit initial softening followed by substantial hardening, with a dramatic increase of the volumetric modulus in denser carbons. Using elastic theory relationships, we estimate the adsorption stresses reaching 175 MPa, that provides crucial insights into potential material degradation mechanisms. For binary CH4/CO2 mixtures, increasing CO2 content amplifies both contraction and expansion effects due to stronger fluid-wall interactions. The iterative MC/MD methodology enables direct observation of the structural evolution and quantitative estimates of the mechanical properties, which are difficult to measure experimentally, advancing our understanding of coupled adsorption-deformation processes in nanoporous materials.
KW - Adsorption
KW - Adsorption-induced deformation
KW - Molecular dynamics simulation
KW - Monte Carlo simulation
KW - Nanoporous carbons
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U2 - 10.1016/j.carbon.2025.120160
DO - 10.1016/j.carbon.2025.120160
M3 - Article
AN - SCOPUS:85219701193
SN - 0008-6223
VL - 238
JO - Carbon
JF - Carbon
M1 - 120160
ER -