Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 6: Charged Soft Matter
CPP 6.4: Talk
Monday, March 14, 2011, 14:45–15:00, ZEU 160
Systematic Analysis of the Surface Structure of Ionic Liquids using Sum Frequency Generation (SFG) — •Markus Reinmöller1,2, Chariz Peñalber2, Gabriela Adamová3, Kenneth R. Seddon3, and Steven Baldelli2 — 1Ilmenau University of Technology, Institute for Physics, Weimarer Straße 32, D-98693 Ilmenau, Germany — 2University of Houston, Department of Chemistry, 136 Fleming Building, Houston, TX 77204-5003, USA — 3Queen’s University Belfast, QUILL Research Centre, David Keir Building, Stranmillis Road, Belfast, BT9 5AG, Northern Ireland (UK)
The surface structure (surface composition and orientation) of phosphonium-based ionic liquids in the system [P888x][Cl] is studied under systematic variation of the length of one alkyl chain (x = 4, 5, 8, 10, 12, and 14) by SFG. The nonlinear optical method of sum frequency generation vibrational spectroscopy (SFG) obtains its surface sensitivity due to the requirement of the broken centro-symmetry, which is present at surfaces and interfaces [1]. Vibrations of both CH2- and CH3-groups from the alkyl chains of the [P888x]+ ion are observed. For this type of phosphonium-based ionic liquids a model for the surface structure will be proposed [2].
Additionally we have performed quantum-chemical calculations using density functional theory (DFT), as demonstrated recently [3].
[1] R. Lu, et al., J. Phys. Chem. B, 108 (2004) 7297. P. B. Miranda, et al., J. Phys. Chem. B, 103 (1999) 3292. [2] C. S. Santos, et al., Chem. Soc. Rev., 39 (2010) 2136. [3] T. Ikari, et al., e-J. Surf. Sci. Nanotech., 8 (2010) 241.