STUDY JET-BLOWING CONDITIONS ON PTFE NANO-FIBERS (nPTFE) AND SURFACE MODIFICATION OF nPTFE USING GAS PLASMA

Open Access
Author:
Chen, Weinan
Graduate Program:
Chemistry
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 10, 2008
Committee Members:
  • John V Badding, Thesis Advisor
Keywords:
  • atmospheric pressure gas plasma
  • jet-blowing
  • nPTFE
Abstract:
Polytetrafluoroethylene (PTFE) is very hydrophobic and difficult to be processed into micro / nano-sized fibers. A new jet-blowing technique developed in our lab could fabricate PTFE nanosized fibers (nPTFE) under high pressure and high temperature condition without using a solvent. There were two aims in this work. First was to study the conditions of jet-blowing process such as gas pressure, gas type and temperature on the effect of nPTFE fiber morphology. These fibers were examined by the mean of scanning electron microscopy. Processing temperature affected the fiber size the most. With higher temperature, the resulting fiber was longer and smoother. Gas pressure caused least effect to fiber size. Secondly, surface modifications of PTFE materials using radio frequency glow discharge (rfGD) gas plasma with different conditions were studied. Samples of nPTFE were exposed to atmospheric plasma containing N2/Ar, O2/Ar, or Ar gas(es). PTFE was exposed to low pressure rf plasma containing NH3 gas. The modified surfaces were characterized by x-ray photoelectron spectroscopy, attenuated total reflection infrared spectroscopy and water contact angle measurements shortly after plasma treatment. The most fluorine depletion of nPTFE surface was caused by Ar plasma and least by O2/Ar plasma. Oxygenated and amine functional groups were introduced to treated surfaces.