SUPERHYDROPHOBIC HYBRID INORGANIC-ORGANIC THIOL-ENE SURFACES FABRICATED VIA SPRAY-DEPOSITION AND PHOTOPOLYMERIZATION

We report a simple and versatile method for the fabrication of superhydrophobic inorganic-organic thiol-ene coatings via sequential spray-deposition and photopolymerization under ambient conditions. The coatings are obtained by spray-deposition of UV-curable hybrid inorganic-organic thiol-ene resins consisting of pentaerythritol tetra(3-mercaptopropionate) (PETMP), triallyl isocyanurate (TTT), 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (TMTVSi), and hydrophobic fumed silica nanoparticles. The spray-deposition process and nanoparticle agglomeration/ dispersion provide surfaces with hierarchical morphologies exhibiting both micro-and nanoscale roughness. The wetting behavior-dependent on the concentration of TMTVSi and hydrophobic silica nanoparticles-can be varied over a broad range to ultimately provide coatings with high static water contact angles (> 150 degrees), low contact angle hysteresis, and low roll off angles (< 5 degrees). The crosslinked thiol-ene coatings are solvent resistant, stable at low and high pH, and maintain superhydrophobic wetting behavior after extended exposure to elevated temperatures. We demonstrate the versatility of the spraydeposition and UV-cure process on a variety of substrate surfaces including glass, paper, stone, and cotton fabric.