(478c) Dynamics of Wetting Transitions in Complex Systems
AIChE Annual Meeting
Wednesday, November 10, 2021 - 1:10pm to 1:30pm
First, for SLV systems, the dynamics of the wetting transitions are presented both experimentally and theoretically with water-air-silicon wafer systems where the Wenzel state is always the thermodynamically favorable state, while a temporary metastable Cassie-Baxter state can also exist to determine the variables that control the rates of such transitions. Theses variables are identified to affect the rate of wetting transition: (i) the intrinsic contact angle, (ii) the concentration of dissolved air in the bulk water phase, (iii) the liquid volatility that determines the rate of capillary condensation inside the cavities, and (iv) the presence of surfactants.
Secondly, for SL1L2 systems, oil-water-silicon wafer systems were used to investigate the rate of wetting transition. When two liquids are involved, one encounter oil-water mixture most frequently during dairy processes and enhanced oil recovery with low-salinity water flooding. The experiments with deionized water revealed that solubility and diffusivity were the driving factors that promoted the replacement, and the 3D confocal images confirmed the decrease in volume of hydrocarbons due to dissolution and diffusion. To exclude these factors, water was saturated with each of the seven hydrocarbons prior to experiments. For these experiments, the adhesion energy of hydrocarbons to the solid surface and the density difference between hydrocarbons and water were correlated with the rate.