Preparation, Superhydrophobic And Anti-icing Properties Of Fluorinated Nano Hybrid Coatings

Superhydrophobic surface is refered to material surface with stable water contact angle greater than 150°and rolling angle less than 10°. Fromation of superhydrophobic surface results from combination of micro-nano composite roughness structure and hydrophobic chemical groups. Due to the special surface wettability, superhydrophobic materials are widely used in antifouling coatings, antibacterial coatings, marine coatings, three proofing finishing agent, biocompatible materials, self-cleaning materials, and so on. How to effectively build superhydrophobic surface and expand its applications in some emerging fields have become the focus of the researchers.In this article, the fluorinated nano hybrid coatings were prepared via hydrolytic condensation of nanosilica sol, methyltriethoxysilane (MTES) and 3-[(Perfluorohexyl sulfony) amino]propyltriethoxysilane (HFTES) based on simple sol-gel method. The superhydrophobic, oleophobic and self-cleaning properties of the hybrid coatings were investigated. The superhydrophobic and anti-icing properties of the colloid surfaces under overcooled temperature were studied. By analyzing the results of SEM, AFM and XPS, we confirmed an obvious enrichment of fluorocarbon chains may occur onto the outmost surface of the coating. As increased HFTES content, surface chemical composition varied. While with increasing of silicasol content, multiscale roughness structure can be obtained. The influence of surface roughness and HFTES on the wettability were explored through contact angle measurement, and 30 wt% silicasol content can result in micro-nano composite structure. At this time, when HFTES content was higher than 6 wt%, the prepared hybrid coating showed superhydrophobicity with water contact angle about 166° and sliding angle or contact angle hysteresis less than 5°. With further increasing HFTES content to 30 wt%, the prepared sol-gel surface exhibited olepphobicity with static contact angle of 143°,102°,136° for glycol, n-hexadecane and diiodomethane respectively. What’s more, the superhydrophobic and oleophobic coating showed multiple liquid-repellent performance, since it can maintain superhydrophobicity in oil phase, and keep outstanding resistance to blood and protein adhesion.Further investigation of superhydrophobic and anti-icing performances under overcooled temperature showed the hybrid films with high HFTES content could maintain excellent superhydrophobic performance under supercooled conditions. Samples of HFTES-30 wt% and HFTES-40 wt% showed superhydrophobicity under-20℃ with water contact angle greater than 160° and sliding angle less than 10°, while samples of HFTES-6 wt% and HFTES-10 wt% would lose superhydrophobicity. More importantly, freezing delay time longer than 1760s for samples HFTES-30 wt% and HFTES-40 wt% showed they can be useful for anti-icing under extremly conditions.