Berlin 2015 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: P1: Interfaces and Thin Films
CPP 15.8: Poster
Montag, 16. März 2015, 16:00–19:00, Poster A
Ultrafast structural dynamics of membrane-bound water molecules revealed by two-dimensional surface-specific vibrational spectroscopy — •Ruth Livingstone1, Zhen Zhang1, Lukasz Piatkowski2, Huib J. Bakker2, Mischa Bonn1, and Ellen H. G. Backus1 — 1Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany — 2FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
We explore the structure and structural dynamics of water in contact with a model lipid membrane (a DPTAP monolayer) using ultrafast time-resolved 2-dimensional sum-frequency generation spectroscopy. With this highly surface-specific technique we monitor the ultrafast frequency fluctuations of the O-H stretch vibrations, that directly reflect the structural dynamics of the water hydrogen-bonding network. For water interacting with a lipid membrane the frequency correlations decay on a sub-picosecond timescale. This timescale does not change upon isotopic dilution of the water, revealing that the fast spectral dynamics are not the result of Förster energy transfer, as previously observed at the water-air interface, but rather result from ultrafast fluctuations in the local hydrogen-bonding network of membrane-bound water molecules.