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BP: Fachverband Biologische Physik
BP 21: Membranes and Vesicles II
BP 21.8: Vortrag
Dienstag, 1. April 2014, 15:45–16:00, ZEU 250
Water-mediated forces at hydrophilic and hydrophobic surfaces — •Matej Kanduc1, Emanuel Schneck2, and Roland Netz1 — 1Free University Berlin, D-14195 Berlin, Germany — 2Institut Laue-Langevin, Grenoble, France
Using all-atom molecular dynamics simulations, we study water-mediated interactions between surfaces of various polarities in order to elucidate the relation between the repulsive hydration and attractive hydrophobic forces. We find that the hydration forces are oscillatory in the stiffer membranes, whereas monotonically-decaying in softer ones and they correlate with oscillations in density profiles. Based on the simulations at prescribed chemical potential and the free energy analysis, we determine the "Berg limit" crossover, which delimits the repulsive and attractive regimes. The surface attraction appears as a result of water cavitation, since the liquid water between the membranes becomes metastable with respect to vapor phase. We also show that the attraction repulsion regimes highly correlate with the formation and breaking of overall hydrogen bonds upon bringing the surfaces in close-contact state.