Realizing the flexible and transparent highly-hydrophobic film through siloxane functionalized polyurethane-acrylate micro-pattern

The superhydrophobic surface has received significant attention in both academic research and industrial applications. Several polymer-based functional films have been reported to produce superhydrophobic water-repellent films with optical transmittance over the years. However, most polymer materials have an aging issue when they exposed to sunlight for a long time. Herein, we propose a facile and cost-effective fabrication method for the preparation of a flexible and transparent highly hydrophobic PUA film. The intrinsic hydrophilicity of PUA has been successfully modified by forming the microstructures and surface modifications with low surface energy siloxane. The siloxane functionalized µ-patterned PUA film was investigated in detail by various material characterization techniques. The obtained results are consistent and confirm the successful formation of the siloxane functionalized µ-patterned PUA film. The siloxane functionalized PUA film achieved the highest water contact angle (WCA)of ∼146°. Also, the fabricated PUA film maintained the WCAs more than 140° even after 50 times bending motions at the bending angle of ∼60° demonstrating the high flexibility of the proposed hydrophobic structure. Furthermore, the suitability of the as-fabricated siloxane functionalized PUA film as a protection layer for a solar cell, and CMOS camera was also systematically proved by the almost unchanged photovoltaic conversion efficiency (PCE)of the solar panel and the high fidelity of the recorded video.