Surface wettability effect on fluid transport in nanoscale slit pores

Abstract

The surface wettability effect on fluid transport in nanoscale slit pores is quantitatively accessed by using nonequilibrium molecular dynamics (NEMD) simulation incorporating with density functional theory (DFT). In particular, the slip lengths of benzene steady flows under various wetting conditions are computed with NEMD simulations and a quasi-general expression is given, while the structural properties are investigated with DFT. By taking into account the inhomogeneity of fluid density inside pore, we find that the conventional flux enhancement rate is associated with both the molecule slipping and geometrical confinement, and it becomes drastically high in solvophobic pores especially when the pore size is of several fluid diameters. In good agreement with experimental results, we further show that the wettability effect competes with pore size effect in determining the flux after pore inner surface modification, and a high flux can be achieved when the deposited layer is solvophobic yet thin.

Effect of Surface Type on the Flow Characteristics in Shale Nanopores

“…Furthermore, unlike the slug-like velocity profiles in the graphene nanopore, the velocity profiles in quartz nanopore are parabolic, which are in agreement with the descriptions of the traditional Navier-Stokes equation [23,46]. Such different slip behavior of methane molecules on the quartz and graphene surface is interesting; the different liquid-solid interactions are generally regarded as the main reason, which is mainly dominated by the atom's parameters σ and ε [64,65] in Table 2 for the CH 4 molecules confined in various nanopores. In addition, the breakdown of gas molecules slippage on the quartz surface is especially owing to the inherent atomic roughness of the surface by Yu et al [43,66], especially, the potential energy roughness of the quartz surface is higher than that on graphene surface up to two magnitude of orders.…”

A molecular model for ion dehydration in confined water

“…The interaction between water molecules and wall is the same as above. The interaction energy strength determines the surface wettability, and the wall here is weakly hydrophilic . Similarly, the water structure is irrelevant with the ion‐wall interaction.…”

“…Many chemical processes involve molecular diffusion and chemical reaction at interfaces, in which the interface‐induced fluid microstructure significantly affects the process efficiency . To improve the process efficiency, numerous studies on fluid structures at interfaces and their intrinsic relations with the interfacial properties have been conducted . Ion hydration represents an important research topic on fluid microstructure.…”

Effect of pore geometry on nanoconfined water transport behavior

“…63 Zhao et al have implemented related research on water flow capacity within nanoslits by using nonequilibrium molecular dynamics simulation incorporating with density functional theory. 64 Notably, the two works are focused on water transport capacity through nanoslits. At this point, it should be highlighted that there is little previous research to shed light on effect of pore shape on nanoconfined water flow, therefore no published data for elliptical nanopores are collected in this section, which further means that reliability of the proposed model cannot be directly validated.…”