Nanoporous Materials

Organic microporous materials offer a new approach for environmentally conscious and energy efficient gas storage and separation technology, such as O2/N2 separation, methane purification, and CO2 capture. Our simulations focus on developing an atomistic understanding of the porous structures of these materials, as well as the interactions between the gas and sorbent matrix. Combined with the experimental work of our collaborators at Penn State, Virginia Tech,  Purdue University, the University of Manchester, and Cardiff University, we aim at determining important design principles of novel nanoporous polymers.

PIM-1 segment (left) and OMIM-1 (right)

PIM-1 segment (left) and OMIM-1 (right)

Our research group is using molecular simulations to study novel nanoporous compounds like polymers of intrinsic microporosity, organic molecules of intrinsic microporosity, as well as hypercrosslinked polymers. Polymers of intrinsic microporosity (PIMs) represent a unique class of polymers based on the design principle that rigid and non-linear or non-planar repeat units derive “intrinsic microporosity” through space-inefficient packing. Organic molecules of intrinsic microporosity (OMIMs) are “small” molecules based on the same design philosophy. The awkward, concave shapes of OMIMs prevent the molecules from packing densely, allowing pores to form. Porosity in hyper-crosslinked polymers (HCPs), on the other hand, is induced by crosslinking polymer chains in a solvated state. The increased free volume present during solvation allows for the formation of pores once the solvent is removed.

 

H2 adsorption in a HCP

H2 adsorption in a HCP

In silico characterization of the simulated structures is performed to help interpret experimental data and further the understanding of the materials’ structure-property relationships. We employ a suite of characterization techniques to determine surface areas, pore-size distributions, and X-ray scattering patterns. Additionally, we perform grand canonical Monte Carlo (GCMC) and Gibbs Emsemble to study the adsorption of different gases. We utilize our own structure generation methodology, Polymatic, which provides consistent and predictive models of these complex materials (see our Polymatic page for more information). Molecular dynamics (MD) and adsorption simulations are performed using software packages including LAMMPS and MCCCS Towhee.

 

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