UC Irvine

In this report I investigate the properties of water interfacing with various crystalline surfaces, by studying its adhesivity as a function of temperature. Through direct visualization of the liquid-solid interface, I report the wetting behavior of water on silicon carbide, oxygen, hydrogen and fluorine terminated CVD diamond, and epitaxial monolayer graphene along the liquid-vapor coexistence curve by varying the temperature from room temperature to ∼ 550 K. Wetting transitions were identified by both vanishing contact angles (SiC, graphene) and drop-wise to film-wise condensation (all samples). Both methods yield similar wetting temperatures, which are 489±9 K, 480±10 K, 530±10 K, 505±2 K and 509±6 K for SiC, o-diamond, h-diamond, f-diamond and graphene respectively. Where applicable, we compare our data to predictions from a simple theoretical model and molecular dynamics simulations of the liquid-solid interactions. We also compare our data with previously reported experimental results. Further, with regard to recent experimental data our evidence suggests that monolayer graphene is not transparent to wetting, but instead exhibits ‘translucency’.

This study appends new - and updates existing - information about the interfacial properties of water on technologically relevant substrates. It reviews the underlying science behind the wetting phenomenon and interfacial interactions, and surveys contemporary experimental data regarding these properties for several substrates.

Finally, this study hopes to aid in the design and development of novel medical, optoelectronic, micro- and nano-fluidic devices.