A mechanically robust slippery surface with ‘corn-like’ structures fabricated by in-situ growth of TiO2 on attapulgite

Abstract

Poor mechanical stability and unstable oil layer of slippery liquid infused porous surface (SLIPS) are urgent issues to be tackled for its long-serving life. Herein, a pre-oil-infused mechanically robust hybrid organic/inorganic superhydrophobic coating (SHC) for SLIPS with prolonged longevity was acquired through concerted elaborate design of both micro-nano structures and chemical interactions. Abundant deposition of TiO2 on many stacked attapulgite (APT) nanorods because of covalent bond Ti-O-Si and hydrogen bond contributed to unique biomimetic ‘corn-like’ structures in SHC. The hydroxyl groups on TiO2 surface could also interact with crosslinked polymers PES (polyethersulfone) and PVDF-HFP (poly-vinylidene fluoride-co-hexafluoropropylene) via hydrogen bonds. Because of these strengthened mutual interfacial interactions, these ‘corn-like’ structures are thereby aggregated tightly together to form affluent and vigorous hierarchical nestle-like structures in SHC which not only exhibited robust superhydrophobicity but also provided sufficient capillary length to stabilize oil. The superhydrophobic substrate for SLIPS could withstand 200 cycles harsh Taber rubbing test (Loading = 250 kPa) and still maintained superhydrophobicity. The as-prepared SLIPS demonstrated outstanding 85 ℃ hot water repellence, high shear force stability (4000 rpm/min) and strong acid/alkali resistance owing to excellent oil-locking ability. This study represented a milestone for designing sturdy SLIPS for potential engineering applications.