Preparation and applications of fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/chemically modified cellulose fibers composites

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R _F -(CH ₂ -CHSi(OMe) ₃ ) _n -R _F : n = 2, 3; R _F = CF(CF ₃ )OC ₃ F ₇ : R _F -(VM) _n -R _F ] was found to undergo the sol-gel reaction under alkaline conditions in the presence of chemically modified cellulose fibers treated with N-methylglucamine units ( MeGlu) [Cellu-fiber- MeGlu] and treated with iminodiacetic acid units ( ImDia) (Cellu-fiber- ImDia) to provide the corresponding fluorinated oligomeric silica/Cellu-fiber- MeGlu composites [R _F -(VM-SiO _3/2 ) _n -R _F /Cellu-fiber- MeGlu] and /Cellu-fiber- ImDia composites [R _F -(VM-SiO _3/2 ) _n -R _F /Cellu-fiber- ImDia], respectively. Dodecane and water contact angle measurements showed that these obtained composites can supply a superamphiphobic characteristic on their composite powders surface. The R _F -(VM-SiO _3/2 ) _n -R _F /Cellu-fiber- ImDia composites were applied to the packing material for the column chromatography to separate the mixture of hydrocarbon and fluorocarbon oils. In addition, the R _F -(VM-SiO _3/2 ) _n -R _F /Cellu-fiber- ImDia composites were found to have more effective removal ability for fluorinated aromatic compounds than that for the corresponding non-fluorinated ones from aqueous methanol solutions. Interestingly, it was demonstrated that the R _F -(VM-SiO _3/2 ) _n -R _F /Cellu-fiber- MeGlu composite powders are also applicable to the fabrication of liquid marbles, which are millimeter-sized liquids such as water, glycerine, ethylene glycol and dodecane stabilized by the adsorbed composite powders at air-liquid interfaces.