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 recent research highlight:
Electrohydraulic Power Conversion in Planar Nanochannels
D. Bonthuis et al.
PRL 2009, 103, 144503 (doi)
The electrophoretic mobility of neutral solutes like oil droplets and air bubbles in water has been a highly debated issue for over a century. Conventional theory states that a non-zero zeta-potential cannot exist without mobile charged species present, but the polarity of water molecules is generally not included in the analysis. Using the Navier-Stokes equation, generalized to include the effect of the polar nature of water, we show that the dipolar water ordering does not contribute to the zeta potential of neutral solutes. Nevertheless, rotating electric fields can be used to drive pure water through a neutral nanochannel based on the coupling between molecular spin and vorticity. This electrohydraulic power conversion offers a new alternative for pumping mechanisms in nanodevices.
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Soft matter easily deforms when excited by thermal motion or by external fields and is
abundant in biological and synthetic systems. Typical questions concern electrostatic effects,
water structure, complexes of polymers and colloids, or non-equilibrium hydrodynamics at structured
surfaces (for more info see the research page).
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 recent research highlight:
Peptide adsorption on a hydrophobic surface results from an interplay of
solvation, surface and intrapeptide forces
D. Horinek et al.
Proc. Nat. Acad. Sci. USA 2008, 105, 2842
(doi)
see also a recent
TUM press release
The hydrophobic effect in protein folding involves structural changes on all length scales,
and the various energy contribution cannot be disentangled. We address this issue by looking at the force
necessary to peel a single spider silk molecule from a flat hydrophobic diamond surface in the presence of
water. Using atomic-force spectroscopy, we determine the mean desorption force as F = 58 ± 8 pN.
All-atomistic MD simulations including explicit water yield F = 54 ± 15 pN. An energy analysis shows
that solvation effects, dispersion, and intrapeptide forces give contributions have to be taken into account.
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We use a wide arsenal of analytical and simulation techniques, ranging from hydrodynamic simulations
over Green’s-functional approach to quantum-chemistry ab-initio calculations, for describing soft
matter systems. Our group is located at the Technical University in Munich. We collaborate
with many of the excellent experimental groups in the region. There are many exciting research topics, so
applications for Diploma and Ph.D. positions are always welcome!
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Conference info:
Ion Specific Phenomena in Physics, Chemistry and Biology (15. - 17.09.08)
 New Journal: Biointerphases
an Open Access Journal for the Biomaterials Interface Community
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Visitors, 10.06.08 |
last update 30.03.2009 by n. schwierz |
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