Atomistic Insights into the Layered Microstructure and Time-Dependent Stability of [BMIM][PF₆] Confined within the Meso-Slit of Carbon

Abstract

Clarifying the microstructures and time-dependent stability of ionic liquids (ILs) within the confinement of the meso-slit of carbon is the first step to understand the intrinsic synergy effect between ILs and a promising mesoporous carbon electrode. In this work, we adopted molecular dynamics to systematically investigate the behavior of [BMIM]­[PF6] in the 2.8 nm-wide meso-slit of carbon. The confined ILs formed a pronounced layered spatial distribution and can be divided into three distinct regions, namely, com-, sub-, and cen-layer, according to valley coordinates in the number density profiles. In the com-layer region, the imidazolium rings of ILs possess two dominant orientations, namely, “parallel” and “tilted standing”. The rotation ability of all the ions is highly restrained. In the sub-layer and cen-layer regions, a part of the [BMIM] imidazolium ring has a preferred “tilted standing” orientation. The [BMIM] cations are still in a rotational restrain state and show a preferred rotation motion along the x–y plane. The hydrogen bond between [BMIM] cations and [PF6] anions play a crucial role in determining the confined multilayered spatial distribution and distinctive orientation properties of ILs.

Probing the nanofriction of non-halogenated phosphonium-based ionic liquid additives in glycol ether oil on titanium surface

“…8). The observed three distinct layers agreed well with a recent simulation findings, in which, the slits confined IL exhibits an apparent triple layered spatial distribution [69].…”

Atomistic insight into the lubrication of glycerol aqueous solution: The role of the solid interface‐induced microstructure of fluid molecules

“…In our previous work, for fluid microstructures in the graphene slit, we found that the H‐bond density of fluid molecules is inhomogeneous 63 . The heterogeneous H‐bond structure near the interface may lead the friction coefficient to present a nonlinear change for glycerol aqueous solutions within graphene slits.…”

Molecular Understanding of the Solid Interface-Induced Microstructures of 1-Hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide in Gas Absorption

“…In our previous work, 38 we found that the nanoconfined imidazole-type IL, ([BMIM][PF 6 ]), can exhibit a pronounced layered spatial distribution. The characteristic orientations of the imidazole rings of ILs in the region nearest to the solid surface are considerably different from those in other regions.…”

“…The carbon atoms in the graphene walls and the titanium and oxygen atoms in the rutile(110) walls were modeled as rigid LJ spheres. The carbon parameters of graphene 38,45 and the titanium parameters and the oxygen parameters of rutile(110) walls 46,47 are shown in Table 2. These parameters were the same as those in our previous works.…”

“…16,36,37 For [BMIM][PF 6 ], we found that nanoconfined ILs can exhibit a pronounced layered spatial distribution and that each layer has distinct characteristic microstructures. 38…”