Surface Activation Of Non-Porous Perfluorinated Polymers By Deposition Of Silica

A method to enhance the surface energy of non-porous films of three different types of perfluorinated polymer [polytetrafluoroethylene with and without a perfluorinated modifier and poly(tetrafluoroethylene-co-hexafluoropropylene)] is described. The surface was activated by the deposition of silica, produced in situ from SICl4 and water, without any chemical degradation or modification of the polymer bulk. By adding perfluorohexane and 1,1,1,3,3,3-hexafluoroisopropanol as auxiliaries to the SiCl4 and water in the gas phase respectively, extended silica layers with spherical morphologies could be generated, which were permanently fixed to the films. By use of low voltage scanning electron microscopy (LVSEM) it was shown that the adhesion of the silica to the fluoropolymers is due to its mechanical anchoring, ultimately resulting from the diffusion of SiCl4 and water into the polymer surface. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.