Fabrication of silicone modified polyurethane matrix superhydrophobic coating with hydroxy-terminated polydimethylsiloxane modified SiO2 nanoparticles

Superhydrophobic coatings have been widely used in anti-icing, anti-fouling, self-cleaning, etc., but the production and application of superhydrophobic coatings have been restricted due to the large amount of fluorine-containing substances. Therefore, the development of an environmentally friendly preparing technology is still a severe challenge. In this article, the hydroxy-terminated polydimethylsiloxane (PDMS) was used as a modifier to replace the general fluorine-containing substance as a modifier to hydrophobically modify the SiO2 nanoparticles. Meanwhile, silicone modified polyurethane (SIPU) was used as an adhesive to prepare a new type of superhydrophobic coating by spraying. The results showed that the hydrophilic SiO2 nanoparticles were converted into hydrophobic SiO2 nanoparticles successfully by grafting PDMS onto the surface of SiO2 nanoparticles. By controlling the content of PDMS@SiO2 nanoparticles, the water contact angle (WCA) and water sliding angle (WSA) of PDMS@SiO2/SIPU composite coating could reach 156.29 ± 1° and 3 ± 1°. Simultaneously, the coating exhibited excellent roughness, wear resistance and special self-cleaning ability. Furthermore, the motion state of the water droplets impacting on the superhydrophobic surface was discussed in detail. The bounce state, splash shape and movement direction of the sub-droplets were closely related to the impact speed, which simulated the outdoor actual raindrop impact.