A robust, flexible superhydrophobic sheet fabricated by in situ growth of micro-nano-SiO2 particles from cured silicone rubber

Here, we report a multifunctional superhydrophobic material achieved through the in situ growth of micro-nano-SiO2 particles from the surface of a preswollen silicone rubber sheet by sol-gel methods. The contact angles of the sheets reached 162 degrees. The scanning electron microscopy (SEM) photographs showed that 0.8-1m SiO2 microspheres grew in situ on the surface of the silicone rubber sheets. The microspheres had 30-70nm nanoscale bulges on their surfaces that formed micro-nano-structures, like a lotus leaf. The sizes of the micro-SiO2 particles and nanobulges were both controllable. The superhydrophobic sheets showed excellent water repellency and self-cleaning performance and exhibited satisfactory durability against mechanical abrasion, rubbing, bending, and long-term underwater storage. The mechanical robustness was attributed to a thick micro-nano-SiO2 layer formed on the surface instead of a monolayer hydrophobic coating. The superhydrophobic rubber sheets were not fluorinated, demonstrated robustness and elasticity, were easy to prepare, and were expected to provide unique advantages for a wide range of applications in biomedicine, energy and electronic devices. [GRAPHICS] . HighlightsA multi-performance superhydrophobic rubber sheet is prepared.Superhydrophobicity is achieved by growing lotus-like structure on cured rubber.Morphologies of the lotus-like structure are controllable.Superhydrophobic sheets have good durability against various mechanical damages.