Physical properties and nanostructuring of long-chained homobaric imidazolium ionic liquids

Abstract

Understanding the structure–property relationship and nanoscopic behaviour of ionic liquids is of utmost importance for their potential applications. Focusing these studies on sets of homobaric ionic liquids could provide important insight into the effects of specific chemical groups on the overall interaction profile, bringing researchers one step closer to succesfully designing ionic liquids which are tailor-made for specific applications. This work focuses on ionic liquids with 12 total carbons on their side chains, studying both their bulk physical properties (such as densities and viscosities) and their nanostructuring. The results reveal that by keeping the total number of carbons constant, but arranging them differently around the imidazolium ring, either in a linear or in a branched-chain formation, can result in compounds with quite distinct properties. Some of those (such as diffusivity) appear to be more sensitive to symmetry variations, while others (such as density) are not significantly affected. X-ray scattering is used in order to get a clearer understanding of the nanostructuring of the studied compounds and to investigate to what extent the observed macroscopic properties are directly linked to the nanoscale ordering.