Surface Modification Of Polytetrafluoroethylene Research Articles

Surface modification of polytetrafluoroethylene by microwave plasma downstream treatment

The surface modification of polytetrafluoroethylene (PTFE) by microwave plasma treatment was investigated by means of contact angle measurement and e.s.c.a. studies. Various gases (e.g. O 2, O 2 N 2 , NH 3) were used. The influence of the various plasma parameters, such as power, gas flow, distance between the sample and the centre of the discharge, treatment time, etc., has been evaluated. No modification was induced by O 2 and O 2 N 2 treatment, whatever the treatment conditions. NH 3 plasma irradiation, however, rendered the PTFE surfaces more hydrophilic, leading to an increase of the polar component of the surface energy from 4.5 to ∼ 57 mJ m −2 under optimized treatment conditions. NH 3 treatment led to defluorination, crosslinking, hydrocarbon (CC,CH) bond formation, and incorporation of nitrogen-containing groups, as confirmed by e.s.c.a. Oxygen was also detected at the surface of treated PTFE. Correlations between the contact angle, defluorination rate, and surface nitrogen and oxygen contents, have been established. Optimization of operational NH 3 plasma parameters, leading to the best wettability of the treated samples, is also reported.

Surface Modification of Polytetrafluoroethylene and the Deposition of Copper Films

AbstractEnhancement of the adhesion of thin copper films on polytetrafluoroethylene substrates was found when the substrate surface was irradiated with a pulsed UV excimer laser prior to metal deposition. The interaction between the laser and the polymer was examined by characterizing the neutral and charged species emitted from the surface during irradiation. The nature of the species emitted indicates that significant chemical modification of the polymer surface occurs. In addition to chemical modification, the interaction with the laser also alters the surface morphology of the polymer. Irradiation at fluences of ∼ 0.6 J/cm2 results in an overall planarization of the surface, whilst irradiation at higher fluences results in the formation and enlargement of voids and localized melting.

Surface Modification of Polytetrafluoroethylene by KrF-Laser Irradiation

Abstract The adhesive strength of polytetrafluoroethylene (PTFE) film was enhanced remarkably by KrF-laser irradiation in air when a small amount of aromatic polyester (APE) was blended with PTFE.

Aging of fluoropolymers irradiated by X-Rays, low energy electrons and energetic heavy ions

Abstract Polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) samples have been irradiated with X-rays, electrons and energetic heavy ions. Changes of electronic structure and chemical bonding have been studied by X-ray photoelectron spectroscopy (XPS). Under electron bombardment, a surface modification of PTFE is first observed (C =. C bond formation). Then bulk reticulation and new bond creation appears The variation of the C15 line with detection angle shows that the graphitization like process is restricted to the surface atomic layer. After the electron bombardment, a slow evolution of the polymer is observed as a function of time (aging process). PVDF appears to be more sensitive to ionizing radiation than PTFE. Indeed, modifications are observed under the X-ray probe. Rational mechanisms are proposed to explain the observed changes.

Polytetrafluoroethylene surface modification by impregnation with iron and manganese oxides

AbstractPolytetrafluoroethylene (PTFE) surfaces can be modified by impregnation with Fe and Mn oxides by procedures based on Fe(CO)5 sorption in the polymer and followed by oxidation with H2O2 or KMnO4. The effect of some variables (reagent concentrations and temperature) on the amount of oxides deposited was examined. The oxides incorporated in PTFE can be only partly removed by acid cleaning. Water–PTFE contact angles and PTFE surface resistivity are altered. Electron and x‐ray diffractograms of the oxides were obtained but unambiguous identification was not achieved. Transmission electron microscopy examination of surface replicas showed that impregnation with oxides which covered most of the PTFE surface was fairly uniform.