Structural Interpretation of Plasma-polymerized Tetrafluoroethylene

Abstract

Structural interpretation of plasma-polymerized tetrafluoroethylene produced in a glow discharge chamber is given by referring to 19F-NMR and IR spectroscopy, elemental analysis, and number-average molecular weight determination. The polymer is hardly soluble in the usual organic solvents because of its highly branched structure, making NMR spectroscopy and molecular weight determination impossible. However, the polymer is soluble in 1,2-dibromo-1,1,2,2-tetrafluoroethane and the following structural interpretation could be obtained. The number-average molecular weight is 3600 for the majority of the polymer, consisting of 96 carbon and 129 fluorine atoms within a unit molecule. The IR spectrum shows evidence of some C=C groups and the 19F-NMR spectrum a highly branched and cross-linked structure in which a large number of quaternary carbons are involved in the polymer matrix as compared with CF2 and CF carbons. The plasma-polymerized tetrafluoroethylene has been characterized in a somewhat different way from the plasma-polymerized ethylene, involving a small number of quaternary carbons.

Molecular composition of films and solid particles polymerized in fluorocarbon plasmas

“…19 In such a large molecule detected in the GPC measurement, the radical site can be ignored for determining molecular weight distribution of the polymerized fluorocarbon molecule. 20 The prepared sample in the THF solution was injected into the GPC column after a filtration process to remove insoluble substances. The column separated the composites of the sample into several groups depending on their molecular sizes.…”

Similarity of Plasma-Polymerized Tetrafluoroethylene and Fluoropolymer Films Deposited by rf Sputtering of Poly(tetrafluoroethylene)

“…Considerable literature exists on the infrared (IR) or X-ray photoelectron spectroscopic (XPS) characterization of the products obtained from plasma polymerization of tetrafluoroethylene (TFE), − and a somewhat smaller body of literature exists on the IR or XPS characterization of the fluoropolymer deposits formed in the rf plasma sputtering of poly(tetrafluoroethylene) (PTFE). ,,− Several references have noted that the structures of the fluoropolymer deposits arising from rf-sputtered PTFE (SPTFE) were similar to those of plasma-polymerized TFE (PPTFE). − ,, In none of these earlier studies were SPTFE and PPTFE prepared in the same plasma reactor. Tibbitt et al, who apparently first reported the remarkable similarity of the IR spectra of PPTFE and SPTFE, suggested that the mechanism of rf sputtering of PTFE resembled that of plasma polymerization of TFE.…”

“…Considerable literature exists on the infrared (IR) or X-ray photoelectron spectroscopic (XPS) characterization of the products obtained from plasma polymerization of tetrafluoroethylene (TFE), [1][2][3][4][5][6][7][8][9][10][11][12] and a somewhat smaller body of literature exists on the IR or XPS characterization of the fluoropolymer deposits formed in the rf plasma sputtering of poly(tetrafluoroethylene) (PTFE). 9,10,[13][14][15][16][17][18][19][20][21] Several references have noted that the structures of the fluoropolymer deposits arising from rf-sputtered PTFE (SPTFE) were similar to those of plasma-polymerized TFE (PPTFE).…”

NMR Study of the Radiation-Induced Cross-Linking of Poly(tetrafluoroethylene-co-perfluoromethyl vinyl ether)

“…Hewes et al used 19 F and 13 C MAS NMR spectroscopy to follow the direct fluorination of ion exchange resins. Plasma-polymerized tetrafluoroethylene (PPTFE) was shown to consist of a highly branched cross-linked network using 19 F NMR . The high-resolution 19 F magnetic resonance of solids has been reviewed by Harris and Jackson …”