Difluorocarbene modification of polymer and fiber surfaces

Difluorocarbene (difluoromethylene, :CF2) generated by the pyrolysis of sodium chlorodifluoroacetate has been shown to irreversibly modify the surfaces of polymers and fibers. The critical surface tension values of several polymers are shown to decrease with increasing exposure to difluorocarbene vapors and ultimately approach the critical surface tension values of partially fluorinated polyethylenes. The rate-controlling step appears to be the diffusion of difluorocarbene from the precursor to the polymer substrate. The nature of the interaction between difluorocarbene and the polymer surface is unknown; however, the absence of infrared bands due to CF bonds in attenuated total reflection measurements tends to establish the mono-molecular-like character of the modified surface.