(204d) Surface Confinement-Induced First Adsorbed Water Layer and Its Wettability Transition Under Compressive Lattice Strain

A molecular-level description of near-surface water structure and a handy manipulation of its properties are relevant to a broad range of scientific and technological phenomena. Here, through a series of molecular dynamics simulations, we report the observation and characterizations of a solid-like first adsorbed water layer (FAWL) and its tunable wetting transition at three metal surface models, namely, Au (100), Pd (100) and a Pd (100)/Au (100) bimetallic junction. The results reveal that (i) there is a formation of the FAWL, resulting from competitive water-water hydrogen bonding and water-solid interactions, which in turn dictates the wettability at water/metal interfaces, (ii) applying compressive lattice strain to metal substrates can induce interfacial wettability transition, which is mediated by subtle packing changes of the FAWL, (iii) by adjusting the lattice strains, the bimetallic junction can host a switchable wettability transition. We anticipate that those findings provide a rigorous fundamental understanding on how water wets a metal surface and how the wettability can be transited purposely.