(408c) Structure and Dynamics of Confined Ionic Liquids From Atomistic Simulations

Ionic liquids (ILs) are novel specialty materials that are formed by pairing an asymmetric cation and a charge delocalized anion. This combination leads to a dramatic decrease in the melting points of these compounds such that many ionic liquids melt, unlike common salts, below room temperature. Owing to a combination of properties such as negligible vapor pressure, excellent solvation ability towards polar and nonpolar species, high electrical conductivity, high thermal stability and a large liquidus range, ILs are being investigated for a range of applications including gas separating agents, catalytic reaction media, solvents in electrochemical devices, energy storage and heat transfer fluids and lubricants. An especially attractive feature of ILs is that they are bifunctional, such that their properties can be adjusted by changing substituents on the cation or the anion or by combining different cation-anion pairs.

An emerging field in this area is the potential for developing novel hybrid materials that allow manipulation of IL properties due to confinement in mesoporous materials. Development of processes based on these materials will require a fundamental understanding of how IL properties are altered by confinement dimensions, pore shape and interaction with the pore walls.

In this presentation, we will elucidate the effect of confinement dimensions on the properties of ILs from atomistic simulation studies. We will report on the molecular dynamics investigation of ILs, 1-n-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and 1-(3-aminopropyl)-1-methylimidazolium bis(trifluoromethanesulfonyl)imide confined in the cylindrical pores of cristobalite and provide results of the structure and dynamics of these ILs as a function of pore diameters ranging from 10 Å to 30 Å.