On the Origin of Interfacial Resistance in Ideal Nanomaterials

SK Bhatia and RC Dutta, JOURNAL OF PHYSICAL CHEMISTRY C, 127, 2035-2044 (2023).

DOI: 10.1021/acs.jpcc.2c07828

in nanomaterials and membranes, limiting efficiency improvement as system size is reduced. While slow transport of fluids in finitesized materials, found in experiment and simulation, has been imputed to interfacial resistance, the underlying mechanism is unclear, and no theory exists for its prediction. A kinetic theorybased approach for low-density transport in finite nanopores is developed here, which demonstrates interfacial resistance to arise from an entry region of developing flow, in which the transport coefficient is nonuniform. The origin of interfacial resistance is shown to lie in the enhanced influence of short molecular trajectories in the entry region, with increased frequency of wall collision, which reduces the local transport coefficient. It is shown that the relative interfacial resistance is a universal function of a parameter related to length and surface momentum accommodation factor for a given fluid-solid interaction potential. While interfacial resistance is system size-dependent, it approaches a limiting value in long nanopores that is readily determined. Application of the approach to H2 transport in carbon nanotubes using molecular dynamics simulation results shows the apparent interfacial resistance to increase with decrease in nanotube diameter and with increase in fluid- solid interaction strength.

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