Preparation of fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/poly(tetrafluoroethylene) nanocomposites possessing a superoleophilic/superhydrophobic characteristic: application to the separation of oil and water
Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R F-(CH2CHSi(OMe)3) n -R F; R F = CF(CF3)OC3F7, n = 2, 3: R F-(VM) n -R F oligomer] can undergo the sol–gel reaction in the presence of poly(tetrafluoroethylene) fine particles under alkaline conditions to afford the corresponding fluorinated oligomeric silica/poly(tetrafluoroethylene) nanocomposites [R F-(VM-SiO3/2) n -R F/poly(tetrafluoroethylene) nanocomposites]. Interestingly, the modified glass, poly(tetrafluoroethylene) sheet and filter paper surfaces treated with the obtained nanocomposites were found to exhibit a superoleophilic/superhydrophobic characteristic, although the original poly(tetrafluoroethylene) sheet and the modified glass surface treated with the R F-(VM) n -R F oligomeric silica nanoparticles [R F-(VM-SiO3/2) n -R F] can provide the usual oleophobic/hydrophobic and oleophobic/superhydrophobic properties, respectively. The modified filter paper was applied to the separation membrane for the mixture of oil/water. In addition, the fluorinated poly(tetrafluoroethylene) nanocomposite white-colored powders thus obtained were applied to the packing material for the column chromatography to separate the mixture of oil/water and water-in-oil emulsions. We have also studied on the reusability of the present nanocomposite particle powders as the packing material for the separation of not only the mixture of oil/water but also the water-in-oil emulsions, and the colorless oil was quantitatively isolated under similar conditions even after the use of the packing materials five times.
KeywordsFluorinated oligomer Silica nanocomposites PTFE particle Superoleophilicity Superhydrophobicity Separation of oil and water
This work was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI (C) No.16K05891) from the Japan Society for the Promotion of Science (JSPS).
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Conflict of interest
The authors declare that they have no competing interests.
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