Design and preparation of SQ-based superhydrophobic coatings with different substituents for multifunctional applications

Three methoxysilane functionalized cage-like silsesquioxanes (CF3-MSQ, Ph-MSQ and Vi-MSQ) were easily obtained by photo-initiated thiol-ene reaction of mercaptopropyltrimethoxysilane with monovinyl(heptatrifluoropropyl)silsesquioxane (CF3-SQ), monovinyl(heptaphenyl)silsesquioxane (Ph-SQ) and octavinylsilsesquioxane (Vi-SQ), respectively. They were deposited on the surfaces of cotton fabric and Cu sheets via sol-gel chemistry to obtain hydrophobic SQ-coated fabrics and Cu sheets, respectively. The detailed surface features of modified fabrics and Cu sheets were analyzed by FTIR, field emission SEM, XPS and WCA. SQ-based superhydrophobic fabrics with an excellent mechanical stability, chemical stability and photo and thermal stability could show good anti-fouling and self-cleaning abilities. Their omniphobicity to water and oil, SQ-coated fabrics can easily separate oil-water mixtures with efficiencies >99 % at maximum flux values over 96,000 L m−2 h−1. SQ-coated Cu sheets offer excellent corrosion resistance at low corrosion current densities of 3.19*10−2 μA·cm−2, low corrosion rates of 0.37 μm yr−1 with high impedance of 13.3 kΩ cm−2 at 0.01 Hz. Anti-corrosion efficiency was over 99.9 %. The effect of SQ substituents on surface properties and application performances were also investigated. These results indicate modified SQs offer considerable potential in oil-water separation and anti-corrosion, etc.