Trichlorosilane chemisorption on surface-modified poly(tetrafluoroethylene)

Modification of poly(tetrafluoroethylene) (PTFE) by trichlorosilane chemiso rption to hydroxyl-modified (PTFE-OH) and silicate-modified (PTFE/SiO2) PTF E is reported. PTFE/SiO2 was prepared by exposure of PTFE-OH to SiCl4 vapor . XPS and contact angle analyses were consistent with the chemical composit ion of PTFE-OH and PTFE/SiO2. Chemisorption of trichlorosilanes from soluti on produced layers on PTFE-OH and PTFE/SiO2. The FTIR absorption intensity for these layers was consistent with monolayer formation. Monolayers with B r, CF3, CH3, CD3, and CH=CH2 terminal groups were prepared. Relative to deu terated hexadecyltrichlorosilane (DHTS) monolayers on PTFE-OH, higher conta ct angles were observed for DHTS monolayers on PTFE/SiO2 under a greater va riety of deposition conditions. Reflectance FTIR indicated that the monolay ers formed on PTFE-OH and PTFE/SiO2 exhibited crystalline-like order consis tent with a well-ordered monolayer. Thermal annealing of the DHTS monolayer s for several days at 125 degrees C did not produce any significant changes in water contact angles.