title: Pulsed plasma discharge polymer coatings.
abstract: The authors studied a pulsed radiofrequency glow discharge polymer film deposition method (pRFGD) on polyethylene terephthalate (PET), silicon (Si), and potassium chloride (KCl) surfaces, with the aim of better controlling film uniformity and homogeneity. A pulse generator was used to control a conventional 13.56 MHz RFGD circuit to provide plasma on and off times throughout a wide range of duty cycles. Starting monomers included fluorocarbon monomers (C8F16O and C3F6O) and more conventional unsaturated monomers [acrylonitrile (C3H3N) and vinyl trimethyl silane (C5H12Si)]. With each of these monomers progressive, large scale changes in the molecular structure of the plasma deposited films were noted with systematic variations in the RF duty cycle. Film characterizations were performed using electron spectroscopy for chemical analysis (ESCA) and fourier transform infrared (FTIR) analysis. In the case of fluorocarbon (FC) films, systematically decreasing plasma on time at a constant off time resulted in enhanced CF2 and CF3 content compared with that seen with the less highly fluorinated groups. There was virtually no oxygen atom incorporation in the FC films obtained from the oxygen containing monomers. Overall, a dramatic decrease in cross-linking of the FC polymer films was observed with decreasing RF duty cycles. A highly ordered Teflon-like structure was obtained for the lowest duty cycles. In the silane experiments, a systematic variation in the ratio of Si-H/Si-CH3 groups was observed, with this ratio increasing as the RF duty cycle decreased. Experiments with C3H3N revealed an increasing surface density of -CN groups with decreasing RF duty cycle.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Chemistry, University of Texas at Arlington 76019-0138.
authors.forename: V
authors.initials: V
authors.lastname: Panchalingam
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: H H
authors.initials: HH
authors.lastname: Huo
authors.forename: C R
authors.initials: CR
authors.lastname: Savage
authors.forename: R B
authors.initials: RB
authors.lastname: Timmons
authors.forename: R C
authors.initials: RC
authors.lastname: Eberhart
mesh_terms: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D004867:Equipment Design; D004864:Equipment and Supplies; D006801:Humans; D011108:Polymers; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D011108:Polymers