Abstract
The molecular-scale structure of the ionic liquid [C18mim]+[FAP]- near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature- dependent hard X-ray reflectivity, small- and wide-angle Xray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing.
| Original language | English |
|---|---|
| Pages (from-to) | 3733-3737 |
| Number of pages | 5 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 110 |
| Issue number | 10 |
| DOIs | |
| State | Published - 5 Mar 2013 |
Keywords
- Liquid surface
- Resonant scattering
- Surface structure