Grafting of ceramic membranes by fluorinated silanes: hydrophobic features

One of the application of ceramic membranes can be the transfer of a gas into a liquid or the extraction of gas from a liquid through a membrane. The problem is the hydrophilic behaviour of the oxide materials that leads to a natural and important absorption of liquid into the different layers of a membrane. Pressures required, in order to bring the liquid back out of the membrane, especially when the pore diameters of the layers become smaller, are too high and systems cannot support such pressures. Consequently, a mean of making membrane material hydrophobic is developed. The membrane was impregnated by a solution of a fluorinated product. It grafts into the membrane material. Grafting using two different fluorinated silanes, C6F13C2H4Si(OMe)(4) and C8F17C2H4Si(OEt)(3), was investigated. First experiments were made, for instance, on microfiltration membrane with C8F17C2H4Si(OEt)(3). Results of grafting of microfiltration and ultrafiltration membranes with different fluorinated silanes will be given and discussed. (C) 2001 Elsevier Science B.V. All rights reserved.