Durable and transparent superhydrophobic coating with temperature-controlled multi-scale roughness for self-cleaning and anti-icing applications

Superhydrophobic surfaces have significant potential for applications in various fields, including self-cleaning, anti-icing, and water/oil separation. However, fabricating a superhydrophobic coating that is simultaneously transparent and durable has remained a challenge due to the inherent trade-off among these three properties. In this study, we introduce a novel approach to creating a superhydrophobic and highly transparent surface with self-generated multi-scale roughness, eliminating the need for employing nanoparticles of varying sizes. Our approach revolves around developing an inorganic resin using SiO2 nanoparticles and small silica oligomers, synthesized through the sol -gel method. Subsequently, this resin is applied to the surface via spin-coating. Under specific conditions, an inorganic polymerization of TCMS occurs on the surface, leading to the formation of nanofibers and larger nanoparticles in conjunction with the initially deposited silica nanoparticles. This process enables the creation of a surface with multi-scale roughness. We investigate the influence of nanoparticle concentration, functionalization duration, and reaction temperature on surface properties. Our findings reveal that a concentration of 7 % SiO2 nanoparticles, combined with a 4-hour TCMS surface functionalization at 3 degrees C, yields the optimal conditions for fabricating a surface that combines exceptional superhydrophobicity, transparency, and durability. The resulting surface exhibits a remarkable contact angle of 160.8 degrees, a sliding angle of 1 degrees, and an 85 % transmittance rate. Moreover, the coating demonstrates impressive resistance to abrasion for up to 30 cycles and can withstand temperatures as high as 250 degrees C. Additionally, the coating shows enhanced protection against UV radiation for up to 40 h and improved resistance to sand abrasion for up to 30 s, enduring bombardment pressures of up to 6 bars. We also conduct tests on the coating for self-cleaning and anti-icing properties, demonstrating excellent performance.