Preparation and Properties of Superhydrophobic Composite Coatings of SiO_2 Nanoparticals/Silicone Resin

SiO2 nanoparticals/silicone resin composite coatings were prepared by spray-coating,which exhibit superhydrophobicity.Effects of the contents of SiO2 and silicone resin were investigated preliminarily on the hydrophobic properties of coatings.The results indicate that the water contact angle of composite coatings increases with increase of the content of SiO2.When the mass percentage of SiO2 is more than 3wt%,the composite coatings exhibit superhydrophobicity.Meanwhile the mass percentage of silicone resin is 7wt%,the composite coating has a high water contact angle of 151.6 and a small sliding angle of nearly 0.The surface morphologies of coatings were observed by scanning electron microscopy(SEM).It was found that the superhydrophobic composite coating has a rough micro-nanoscale hierarchical structure,with all near-spherical papillas(d≈5 μm) covered by aggregated nanoparticles(d≈50 nm).Such lotus leaf like micro-nano hierarchical structure in combination with the low surface energy of silicone resin renders the coating surface superhydrophobicity.