Preparation Of Hydrophobic SiO₂@?TiO₂/MoS₂? Composite Coating And Superhydrophobic Aluminum Substrate Surface

Inspired by the self-cleaning phenomenon of lotus leaves,superhydrophobic surface with special wettability has attracted considerable interest in recent years.It is important to explore methods of fabricating superhydrophobic surfaces on different substrates,expand their applications and develop other functions.The main contents of this study are as follows:Firstly,a novel dual functional composite film with superhydrophobicity and photocatalytic activity was fabricated on glass substrate based on sol-gel and hydrothermal method.TiO₂/MoS₂ composite photocatalyst with visible light response was first prepared by hydrothermal method.Then TiO₂/MoS₂ was modified by methyltriethoxysilane?MTES?using sol-gel method and hydrophobic SiO₂@?TiO₂/MoS₂?composite particles were adhered with glass substrate tightly using polydimethylsiloxane?PDMS?adhesives.The spectral response range of TiO₂ had been broadened to visible light region by UV-vis analysis due to the introduction of semiconductor MoS₂.FT-IR and XPS analysis showed that hydrophobic SiO₂ had been chemically bonded on the surface of Ti O2/Mo S2 nanoparticles through Si-O-Ti chemical bond.The composite film exhibited stable superhydrophobicity and excellent photocatalytic activity for degradation of methyl orange?MO?when M:T was 7:1.The water contact angle?CA?and degradation efficiency for MO remained at 154° and 94% respectively even after five continuous cycles of photocatalytic reaction.The SEM images showed that the nanoparticles were fused together by adhesive and the surface exhibited a porous structure with dual scale roughness.Further,the composite film showed a good non-sticking characteristic with the water sliding angle?SA?about 4°.Secondly,a superhydrophobic surface with anti-corrosion property on aluminum substrate was prepared by chemical etching and in situ polymerization method.The micro-nano rough structure was constructed on the surface of aluminum substrate based on a simple one-step wet chemical etching method in the HCl solution.The SEM images demonstrated that the aluminum substrate surface showed a rather rough and irregular step-like morphology when the etching time was 3.5 min.Then a superhydrophobic aluminum substrate surface with ultra-low adhesion was formed by the in situ polymerization through thiol-ene click chemical reaction.The WCA and SA were 163° and 5°,respectively.The area fraction of gas-liquid interface in the superhydrophobic aluminum surface was 94.70% calculated by Cassie-Baxter model equation.The as-prepared surface was also demonstrated excellent corrosion resistance in 3.5% wt NaCl solution by the analysis of Tafel polarization curve.The self-etching current density of superhydrophobic aluminum surface was only 3.22×10^-7 A/cm²,lower than the original aluminum surface.And the corrosion potential shifted positively.Furthermore,the superhydrophobic aluminum surface showed excellent thermal stability up to 250?.