Rational Design of Superhydrophilic/Superoleophobic Surfaces for Oil-Water Separation via Thiol-Acrylate...

We report a simple, rapid, and scalable strategy to fabricate surfaces exhibiting in-air superoleophobic/superhydrophilic wetting via sequential spray deposition and photopolymerization of nanoparticle-laden thiol-acrylate resins comprising both hydrophilic and oleophobic chemical constituents. The combination of spray deposition with nanoparticles provides hierarchical surface morphologies with both micro- and nanoscale roughness. Mapping the wetting behavior as a function of resin composition using high- and low-surface-tension liquid probes enabled facile identification of coatings that exhibit a range of wetting behavior, including superhydrophilic/superoleophilic, superhydrophobic/superoleophobic, and in-air superhydrophilic/superoleophobic wetting. In-air superhydrophilic/superoleophobic wetting was realized by a dynamic rearrangement of the interface to expose a greater fraction of hydrophilic moieties in response to contact with water. We show that these in-air superoleophobic/superhydrophilic coatings deposited onto porous supports enable separation of model oil-water emulsions with separation efficiencies up to 99.9% with 699 L·m^-2 h^-1 permeate flux when the superhydrophilic/superoleophobic coatings are paired with 0.45 μm nylon membrane supports.