Theoretical Study of Amino Acid-Based Ionic Liquids Interacting with Carbon Nanosystems

Abstract

The properties of 1-ethyl-3-methylimidazolium glycinate ionic liquid regarding fullerenes, graphene, and single-walled carbon nanotubes are studied using classical molecular dynamics simulations. Endohedral fullerenes forming C60 to C540 containing a variable number of confined ions are studied, and the solvation of these systems by bulk liquid phases is also studied. The adsorption of the ionic liquid on top of graphene sheets and the confinement between two sheets are also analyzed as a function of intersheet separation. Likewise, confinement inside single-walled nanotubes as a function of nanotube diameter is analyzed together with ionic mobility in comparison with bulk phases. External solvation, densification, and layering around the nanotubes are also considered. The properties of these systems involving amino acid-based ionic liquids are compared with available studies involving classical imidazolium ionic liquids with other types of ions.

Molecular-Level Understanding of Structures and Dynamics of Imidazolium-Based Ionic Liquids around Single-Walled Carbon Nanotubes: Different Effects between Alkyl Chains of Cations and Nanotube Diameters

“…As a powerful analysis tool, molecular dynamics (MD) simulation can provide a direct and deep insight into both the interaction mechanism and the relevant interfacial properties between the imidazolium-based ILs and the CNTs at a molecular level. ,− For example, Shim and Kim used MD simulations to demonstrate for the first time that both the [Emim] + cations and the [BF 4 ] − anions always display a smeared-out, cylindrical multishell density distribution around all CNTs with different diameters and that the imidazolium rings of [Emim] + cations in the first solvation shell prefer to be parallel to the CNT surfaces due to the π–π stacking interactions between them. Subsequently, the other orientation pattern was further found from the MD simulation of Huo and Liu, where the imidazolium rings of [Bmim] + cations next to the first solvation shell are perpendicular to the CNT­(6,6) surface with their butyl chains appearing in the first solvation shell.…”

Rheological behavior of multiwalled carbon nanotube-imidazolium tosylate ionic liquid dispersions

“…Some authors have demonstrated that ILs interact with CNTs through cation-π and π−π interactions [19,20] and there are some evidences revealing weak van der Waals interaction without an obvious influence of the electronic structure of CNTs [21]. Moreover, it has been recently proved via X-ray diffraction and molecular dynamics simulations that ILs can be encapsulated inside CNTs and not only on the external surface [22,23].…”

Rheological study of new dispersions of carbon nanotubes in the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide

“…The chemical structure of the ionic liquid is shown in Figure 1. Dispersions of CNTs are prepared by simple addidtion to the ionic liquid in a 1 wt.% proportion following the method described previously by Fukushima [28] and also used in our earlier works [26,34,38,39]. With this procedure, the materials are weighed and mixed in an agate mortar, where manual blend was performed for 10 minutes.…”

“…ILs disperse CNTs through cation-π and π-π [30,31] and van der Waals interactions without an obvious influence of the electronic structure of CNTs [32]. Moreover, it has been proved via X-ray diffraction and molecular dynamics simulations that ILs are not only present on the external nanotube surface but can be encapsulated inside CNTs [33,34].…”