“…Since our FTIR and XPS analyses cannot distinguish between cumulative aromatic rings or substituted benzene rings in our films, time-of-flight (TOF) SIMS spectra were obtained on films deposited from 10/990 pulsed benzene and HFB plasmas (Figure ). Previous SIMS studies of polystyrene (PS) show the dominant peak in the positive ion spectrum is the C 7 H 7 + ion ( m / z = 91), which is assigned as the cyclic tropylium ion, I . , This is also the strongest peak in the SIMS data for our pulsed benzene films. There is, however, a strong C 8 H 9 + signal ( m / z = 105) in our results relative to conventional polystyrene. , This peak is generally assigned to the structure of the styrene repeat unit.…”
Section: Resultsmentioning
confidence: 58%
“…Previous SIMS studies of polystyrene (PS) show the dominant peak in the positive ion spectrum is the C 7 H 7 + ion ( m / z = 91), which is assigned as the cyclic tropylium ion, I . , This is also the strongest peak in the SIMS data for our pulsed benzene films. There is, however, a strong C 8 H 9 + signal ( m / z = 105) in our results relative to conventional polystyrene. , This peak is generally assigned to the structure of the styrene repeat unit. 7 Static SIMS positive-ion spectra of (a) a film deposited from a 10/990 pulsed C 6 H 6 plasma and (b) a film deposited from a 10/990 pulsed C 6 F 6 plasma.…”
Section: Resultsmentioning
confidence: 58%
“…When the off time is further increased to 990 ms (1% duty cycle), the absorbance values for the sp 2 and sp 3 CH stretches are nearly equal. Fine aromatic structure becomes more pronounced with absorbances at 1493 and 1599 cm -1 due to in-plane phenyl ring bending modes and 1451 cm -1 due to a methyl CH bend and an in-plane phenyl ring bend . The out-of-plane phenyl ring bending bands at 754 and 700 cm -1 also become sharper.…”
Pulsed plasma polymerization is used to produce aromatic thin films from inductively coupled rf plasmas with benzene, 1,2,4-trifluorobenzene, and hexafluorobenzene as monomers. The effects of aromatic monomer fluorination and duty cycle variation on the resulting films' properties are examined. The surface and bulk properties of the films are determined using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), static secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM), static contact angles, and differential scanning calorimetry (DSC). Analysis using these techniques shows a strong dependence of film chemistry and deposition rates on the plasma duty cycle. Systematic changes in film chemistry are observed with the lowest duty cycles producing films containing substituted aromatic rings. On the basis of the SIMS, XPS, and DSC data, films deposited under the optimal pulsed conditions are similar to polystyrene in structure but are more complex, somewhat cross-linked networks. These studies show pulsed plasma polymerization affords high control over film chemistry and properties.
“…Since our FTIR and XPS analyses cannot distinguish between cumulative aromatic rings or substituted benzene rings in our films, time-of-flight (TOF) SIMS spectra were obtained on films deposited from 10/990 pulsed benzene and HFB plasmas (Figure ). Previous SIMS studies of polystyrene (PS) show the dominant peak in the positive ion spectrum is the C 7 H 7 + ion ( m / z = 91), which is assigned as the cyclic tropylium ion, I . , This is also the strongest peak in the SIMS data for our pulsed benzene films. There is, however, a strong C 8 H 9 + signal ( m / z = 105) in our results relative to conventional polystyrene. , This peak is generally assigned to the structure of the styrene repeat unit.…”
Section: Resultsmentioning
confidence: 58%
“…Previous SIMS studies of polystyrene (PS) show the dominant peak in the positive ion spectrum is the C 7 H 7 + ion ( m / z = 91), which is assigned as the cyclic tropylium ion, I . , This is also the strongest peak in the SIMS data for our pulsed benzene films. There is, however, a strong C 8 H 9 + signal ( m / z = 105) in our results relative to conventional polystyrene. , This peak is generally assigned to the structure of the styrene repeat unit. 7 Static SIMS positive-ion spectra of (a) a film deposited from a 10/990 pulsed C 6 H 6 plasma and (b) a film deposited from a 10/990 pulsed C 6 F 6 plasma.…”
Section: Resultsmentioning
confidence: 58%
“…When the off time is further increased to 990 ms (1% duty cycle), the absorbance values for the sp 2 and sp 3 CH stretches are nearly equal. Fine aromatic structure becomes more pronounced with absorbances at 1493 and 1599 cm -1 due to in-plane phenyl ring bending modes and 1451 cm -1 due to a methyl CH bend and an in-plane phenyl ring bend . The out-of-plane phenyl ring bending bands at 754 and 700 cm -1 also become sharper.…”
Pulsed plasma polymerization is used to produce aromatic thin films from inductively coupled rf plasmas with benzene, 1,2,4-trifluorobenzene, and hexafluorobenzene as monomers. The effects of aromatic monomer fluorination and duty cycle variation on the resulting films' properties are examined. The surface and bulk properties of the films are determined using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), static secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM), static contact angles, and differential scanning calorimetry (DSC). Analysis using these techniques shows a strong dependence of film chemistry and deposition rates on the plasma duty cycle. Systematic changes in film chemistry are observed with the lowest duty cycles producing films containing substituted aromatic rings. On the basis of the SIMS, XPS, and DSC data, films deposited under the optimal pulsed conditions are similar to polystyrene in structure but are more complex, somewhat cross-linked networks. These studies show pulsed plasma polymerization affords high control over film chemistry and properties.
“…In a plasma polymerization process, the chemical structure of the plasma polymer can be altered by the selection of important parameters, among them being discharge power, gas flow‐rate, pressure, duty cycle, and reactor geometry 3. Plasma polymerization of styrene1,4–10 and plasma surface modification of polystyrene11–13 have been studied several times. However, most of the studies were performed after exposing the samples to air before analysis.…”
Summary: Pulsed plasma‐deposited polystyrene films were studied by time‐of‐flight static secondary ion mass spectrometry (ToF‐SSIMS) before and after exposure to ambient air. The influence of the external plasma parameters on the secondary ion mass spectra of plasma‐deposited polystyrene films was investigated. From these data, information on the chemical character of the plasma polystyrene films was derived. In the range of deposition conditions applied in this study, the fragmentation of styrene is a minor process. The main process is probably the radical chain propagation to polymers. All the polystyrene plasma polymers, relying on ToF‐SIMS, seem to be rather similar to a reference polystyrene oligomer sample. When the plasma polymers are exposed to air, extensive oxygen incorporation occurs. Oxygen uptake was found to alter the emission probabilities of secondary ions. A relation between the regularity of the plasma polymers and the amount of oxygen incorporation was found. The result was that the chemical regularity of the plasma polystyrene decreases when the effective power in the plasma is increased.
“…Two previous reports describe the mass spectrometry of plasmas of styrene. 15,16 In neither of these studies were ions of m/z greater than that of styrene (m/z \ 104) detected and no distinction was made between positively charged and neutral species in the plasma. The work presented here includes mass spectra recorded up to m/z 300 and the experimental conÐguration used allows distinction between positive and neutral species in the plasma.…”
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