Does the thermal motion of macromolecules really influence the fluorine-atomic concentration of plasma-fluorinated polyolefin surfaces?

The relative fluorine-atomic concentrations and the abundance of CF_x functionalities from CF₄- and C₆F₆-RF-plasma treated polypropylene (PP) film surfaces were evaluated. Survey and high resolution (HR) ESCA data indicate that intense surface fluorination can be carried out, from both fluorine precursors, under relatively low power and treatment time conditions. However, it was found that the stability (under open laboratory conditions and under various solvent and temperature environments) of plasma implanted fluorine based groups significantly depend on the nature of plasma gases involved. Simulation of plasma induced molecular fragmentation, at different electron energy MS conditions, indicates the presence of a much higher fluorine atom concentration from a CF₄-plasma in comparison to a C₆F₆-plasma. It is suggested that fluorine atom mediated fragmentation of macromolecular backbones is probably responsible for the erosion of plasma fluorinated surfaces, rather than thermal motion induced burying processes.