Fluorination of polymers by means of He/CF4-fed atmospheric pressure glow dielectric barrier discharges

He/CF 4 -fed GDBDs were used to fluorinate PP and PET. The effect of various process parameters on the polymers surface composition and morphology, as well as on their wettability was investigated inside the GDBD existence domain. An extensive surface fluorination of treated polymers due to the grafting of F atoms and CF x radicals was observed. The increase of CF 4 concentration in the feed, of treatment duration, and of excitation frequency resulted in an increase of the fluorination degree corresponding to F/C ratios as high as 1.18 and 1.22 for PP and PET, respectively. The emission spectra of GDBDs fed by helium in mixture with CF 4 , CHF 3 , C 2 F 6 and C 3 F 8 were compared.