Facile preparation of superhydrophobic surfaces with enhanced releasing negative air ions by a simple spraying method

Superhydrophobic surfaces with micro/nano structures were prepared using the synergistic effect of the hydroxyl-silicone-oil modified microscale tourmaline particles (HTP) and the nanoscale silica (SiO2) by a simple spraying method. The SiO2/HTP/Polyurethane (PU) and HTP/PU dispersions were sprayed onto the waterborne polyurethane (WPU) film using a shower nozzle driven by an air compressor. After drying of the spraying film at room temperature, a surface with micro/nano structures was obtained and the micro/nano structures were consisted of the microscale HTP coated by the nanoscale SiO2. Static water contact angle measurements proved that the rough surfaces were superhydrophobic. Furthermore, their performance of releasing negative air ion was significantly enhanced due to the rough structure. Importantly, this method is simple, low-cost and suitable for the fast and large-scale preparation of superhydrophobic surfaces, which is particularly important for the modification of hydrophilic polymer surfaces.