Plasma polymerization of tetrafluoroethylene and chlorotrifluoroethylene was conducted in a capactive coupling external electrode apparatus. Eesults from IR

X-ray diffraction and elementary analysis show the polymer formed in the glowing region of plasma has a lower concentration of -CF2-groups and therefore it becomes a cross-linked product. IR spectroscopy was used to study some of the optical properties of plasma polymerized films. The films have a better transmittance over a wide spectral range and have good thermostability.