Unprecedented superoleophobicity achieved with fluorinated wrinkle mesoporous silica

Superoleophobic surfaces can be facilely fabricated by utilizing fluoroalkyl-modified wrinkled mesoporous silica (F-WMS). Initially, a hydrophilic wrinkled mesoporous silica (WMS) (average particle size -400 nm) with radial pores and narrow silica walls was prepared, and subsequently modified with a fluoroalkylsilane, specifically 1H,1H,2H,2H-heptadecafluorodecyl trimethoxysilane (FAS -17), to impart low surface energy. Preservation of the WMS pore structure was observed even at a 20 mol% FAS -17 feeding ratio; thus, the resulting F-WMS was designated as F20-WMS. An aluminum substrate was coated with an epoxy resin (EP) for adhesion, followed by spray-coating the F20-WMS suspension onto the EP layer. The resulting EP/F20-WMS coating displayed a notably high static water contact angle (CA) of 172.3 degrees and a low roll -off angle (RA) of 1 degrees Notably, the coating exhibited exceptional oil repellency, showcasing a hexadecane CA of 165.1 degrees and an RA of 4.3 degrees, surpassing the performance of most reported superoleophobic coatings. Plotting cos (CAs on EP/F20-WMS) against (CAs on a flat surface coated with FAS -17), utilizing CA data with various liquids (water - dodecane, 72.1 - 25.3 mN/m, respectively), indicated that the liquids were consistently in Cassie states with a contacting fraction of approximately 0.03 between the liquid droplets and the surface. The unprecedented superoleophobicity of EP/F20WMS was attributed to the extremely low contact fraction and the presence of a re-entrant texture. Moreover, the coatings exhibited exceptional mechanical durability in tape -peeling tests (50 cycles) and achieved the highest adhesion rating (5 B) in cross-cut tests. This superior oleophobicity, coupled with high durability, opens up opportunities for real-life applications necessitating liquid -free surfaces.