Mainz 2017 – scientific programme
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MO: Fachverband Molekülphysik
MO 13: Probing Vibrations
MO 13.7: Talk
Thursday, March 9, 2017, 12:45–13:00, N 6
Distinguishing between silanol O-H and water O-H at the silica/water interface with time resolved SFG spectroscopy — •Jenée D. Cyran1, Michael A. Donovan1, Jonathan F.D. Liljeblad2, Eric Tyrode2, Mischa Bonn1, and Ellen H.G. Backus1 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2School of Chemistry, Division of Surface and Corrosion Science, Royal Institute of Technology, Stockholm, Sweden
The surface properties of silica in contact with aqueous solutions impact a plethora of fields, including geochemical, technological, and biological. Characterizing the silica/water interface on a molecular level is crucial for understanding the adsorption and reaction of water on the silica surface. Sum frequency generation (SFG) spectroscopy, a surface selective technique, affords the ability to use molecular vibrations to characterize the silica/water interface. The vibrational spectrum of this interface reveals a high-frequency feature centered at 3680 cm-1. It has been debated whether this resonance originates from a free O-H from water or from a silanol (Si-O-H) group. Here, we use time- and polarization resolved SFG to distinguish between these two, as the water O-H can clearly reorient much faster than a surface-bound silanol group.