Research highlighted in ChemistryWorld

Graphical representation showing localisation of the [Tf2N]- (red) anions at the ionic liquid-vacuum outer surface

Dr Kevin Lovelock's research on ionic liquid-gas interfaces is featured in ChemistryWorld

Research by Chemistry Junior Research Fellow Dr Kevin Lovelock has been featured in ChemistryWorld.

The team of Dr Kevin Lovelock in the Department of Chemistry, in collaboration with researchers in the Department of Materials at Imperial College London, found that small changes to ionic liquid systems can significantly alter their surface composition. The findings may aid the design of ionic liquid films for applications such as gas capture and supported catalysis, where gas adsorption to the outer atomic surface is essential.

Studies on simple one-cation–one-anion ionic liquids have previously revealed that the outer layers contain a greater concentration of alkyl chains than in the bulk, reducing the number of accessible surface anions. To better understand the behaviour of more complex one-cation–two-anion mixtures, the team probed the outer surface of several ionic liquid mixtures, expecting to find subtle differences between the concentrations of anions at the surface. Instead, the team were surprised by the drastic differences brought about by changes in the nature of the counter anions. Anions with weaker cation–anion interactions were present in much greater numbers at the surface than should be predicted for ideal mixtures. At the heart of the study lies the technique low-energy ion scattering (LEIS), which exclusively probes the outer atomic surface, unlike other techniques used to investigate ionic liquid surfaces to date, such as X-ray photoelectron spectroscopy (XPS).