Development of superamphiphobic alumina nanofiber mats using trimethoxysilane with a short perfluoroalkyl chain

To avoid the generation of hazardous, long-chain perfluoroalkyl carboxylic acids (C _n F _{2 n +1} COOH, n ≥ 7), we develop relatively safer superamphiphobic alumina nanofiber mats. Our fabrication process focuses on two principles: lowering the surface energy using trimethoxy(1H, 1H, 2H, 2H-nonafluorohexyl)silane (C ₄ F ₉ CH ₂ CH ₂ Si(OCH ₃ ) ₃ ), which has short-chain perfluoroalkyls that are relatively safer than long-chain ones; and creating a high-roughness surface from electrospun alumina nanofibers with an average fiber diameter of 155 nm and inter-fiber spacing of 451 nm. Such mats exhibit super-repellency for water (contact angle [Formula: see text] = 157°, contact angle hysteresis [Formula: see text], advancing angle [Formula: see text] 158°, receding angle [Formula: see text] 156°), and n-hexadecane ([Formula: see text] = 151°, [Formula: see text]9°, [Formula: see text] 152°, [Formula: see text] 143°). Furthermore, superamphiphobicity is maintained up to 350℃.