Fluorination of polymethylmethacrylate with SF6 and hexafluoropropylene using dielectric barrier discharge system at atmospheric pressure

Fluorination of PMMA using atmospheric plasmas is highly dependent on the nature of the fluorinating agents and plasma parameters. For example, application of nitrogen plasma to the PMMA leads to surface etching and a decrease of the water contact angle to 57°. With addition of the SF6 to the plasma the etching process is enhanced. Hexafluorosulfide etching is also inhomogeneous along the surface of PMMA where nano-columns formation was observed by atomic force microscopy. In contrast, deposition of fluorocarbon polymer onto PMMA can be accomplished via exposure to hexafluoropropylene (HFP) plasma, resulting in an increased water contact angle of PMMA from 70° to 110°. The standard deviation of the water contact measurements varied from 0.5 to 6° suggesting homogeneous nature of the poly HFP coatings. RMS roughnesses of 0.6 to 0.9 nm were measured for poly HFP films on PMMA deposited by atmospheric pressure plasma discharge system.