Bio-inspired highly hydrophobic surface with ecdysis behavior using an organic monolithic resin and titanium dioxide photocatalyst

In order to develop a durable highly hydrophobic surface, a biomimetic design was developed by combining an organic monolithic resin, TiO2 photocatalyst, and polytetrafluoroethylene particles. An accelerated weathering resistance examination revealed that the highly hydrophobic surface maintained a water contact angle exceeding 140° for 6 years. Moreover, high antiwear performance was confirmed by a rubbing test. Since the organic monolithic resin had co-continual structures with interconnected pores, new surface with a microstructure appeared continually by removal of the damaged surface. On the other hand, decomposition of organic compounds by TiO2 photocatalyst enabled self-etching of the damaged top layer of the organic monolithic resin. The flowing water due to rainfall or physical scraping contributed to the removal of the damaged surface. However, the film thickness after surface restoration was approximately constant. In addition, dynamic hydrophobicity could be improved when interconnected pores of the organic monolithic resins were impregnated with perfluorocarbon liquid. Thus, we have addressed essential issues and proposed a new method for designing hydrophobic surfaces with high durability.