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

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R-F-(CH2-CHSi(OMe)(3))(n)-R-F: n = 2, 3; R-F = CF(CF3)OC3F7: 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-SiO3/2)(n)-R-F/Cellu-fiber-MeGlu] and /Cellu-fiber-ImDia composites [R-F-(VM-SiO3/2)(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-SiO3/2)(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-SiO3/2)(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-SiO3/2)(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.