Structural, hydrogen bonding and dipolar properties of alkyl imidazolium-based ionic liquids: a classical and first-principles molecular dynamics study

TL;DR

This study uses classical and first-principles molecular dynamics to explore the structural, hydrogen bonding, and dipolar properties of alkyl-imidazolium-based ionic liquids, providing atomistic insights into their interactions relevant for electronic applications.

Contribution

It offers a detailed atomistic analysis of chemical bonding, structure, and charge distribution in alkyl-imidazolium ILs, highlighting the influence of anion type and alkyl chain length on hydrogen bonding networks.

Findings

Hydrogen bond strength varies with anion and alkyl chain length.

Structural and dipolar properties are correlated with hydrogen bonding networks.

Insights can inform the design of ILs for electronic device applications.

Abstract

Ionic liquids (ILs) feature a tailorable and wide range of structural, chemical and electronic properties that make this class of materials suitable to a broad variety of forefront applications in next-generation electronics. Yet, their intrinsic complexity call for special attention and experimental probes have still limitations in unraveling the interactions occurring both in the bulk IL and at the interface with the solid substrates used to build the devices. This works provides an atomistic insight into these fundamental interactions by molecular modeling to complement the information still not accessible to experiments. In particular, we shed some light on the nature of the chemical bonding, structure, charge distribution and dipolar properties of a series of alkyl-imidazolium-based ILs by a synergy of classical and first-principles molecular dynamics simulations. Special emphasis is given to the crucial issue of the hydrogen bond network formation ability depending either on the nature of the anion or on the length of the alkyl chain of the cation. The hydrogen bond strength is a fundamental indicator of the cohesive and ordering features of the ILs and, in this respect, might be exploited to foster a different behaviour of the IL used a bulk medium or when used in electronic devices.