Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Posters: Membranes and vesicles

BP 24.1: Poster

Tuesday, March 17, 2015, 14:00–16:00, Poster A

The crossover from hydration repulsion to cavitation-induced attraction between asymmetric hydrophilic and hydrophobic surfaces — •Matej Kanduc and Roland Netz — Department of Physics, Free University Berlin

Utilizing all-atom molecular dynamics simulations at constant water chemical potential in combination with basic scaling arguments, we study hydration-induced interactions between two overall neutral yet polar planar surfaces with different wetting properties. Whether the water film between the two surfaces is unstable and cavitation gives rise to long-range attraction, depends on the sum of the two individual surface contact angles. Consequently, cavitation-induced attraction also occurs between a hydrophobic surface and a mildly hydrophilic surface. If both surfaces are hydrophilic, hydration repulsion prevails. In between the regimes of cavitation-induced attraction and hydration repulsion we find a narrow range of contact angles where the two surfaces adhere without cavitation. The extent of this regime depends on the inter-surface adhesion properties. Simple scaling laws for the onset of cavitation and the adhesion transition are presented and favorably compared with simulations in a generic phase diagram as a function of the two surface contact angles.