Trichlorosilane Chemisorption on Surface-Modified Poly(tetrafluoroethylene)

Modification of poly(tetrafluoroethylene) (PTFE) by trichlorosilane chemisorption to hydroxyl-modified (PTFE−OH) and silicate-modified (PTFE/SiO 2 ) PTFE is reported. PTFE/SiO 2 was prepared by exposure of PTFE−OH to SiCl 4 vapor. XPS and contact angle analyses were consistent with the chemical composition of PTFE−OH and PTFE/SiO 2 . Chemisorption of trichlorosilanes from solution produced layers on PTFE−OH and PTFE/SiO 2 . The FTIR absorption intensity for these layers was consistent with monolayer formation. Monolayers with Br, CF 3, CH 3, CD 3, and CH CH 2 terminal groups were prepared. Relative to deuterated hexadecyltrichlorosilane (DHTS) monolayers on PTFE−OH, higher contact angles were observed for DHTS monolayers on PTFE/SiO 2 under a greater variety of deposition conditions. Reflectance FTIR indicated that the monolayers formed on PTFE−OH and PTFE/SiO 2 exhibited crystalline-like order consistent with a well-ordered monolayer. Thermal annealing of the DHTS monolayers for several days at 125 °C did not produce any significant changes in water contact angles.