Search

PTFE (polytetrafluoroethylene) has superior characteristics such as low dielectric constant, low dielectric tangent, and chemical stability. However, it has a low adhesion force. In order to improve the adhesion force, we have studied the surface modification of PTFE by using a discharge under high E/ n ( E is the electric field, n is the particle density) conditions in nitrogen. Under high E/ n conditions, electrons and ions achieve energies up to and exceeding 100 eV. It is inferred that improvement of adhesion is brought about by the introduction of polar groups at the surface. However, it is not clear which particles (ions, atoms, excited molecules, etc.) in the discharge space promote the introduction of polar groups into the PTFE surface. We assume that ions with high kinetic energies rather than the binding energy of PTFE contribute to the formation of chemical bonds by breaking C-C or C-F bonds. It is expected that bond cleavage is the rate-determining step in surface modification. We measured the contact angle of samples irradiated at various ion energies and exposure doses. The results indicate that increasing the exposure dose accelerates the introduction of polar groups. In addition, it is inferred that an ion energy of about 40 eV is effective for the introduction of polar groups. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(1): 1-7, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.21226 [ABSTRACT FROM AUTHOR]

The authors irradiated PTFE (polytetrafluoroethylene) with low-energy nitrogen ions (100 eV) for surface modification. However, PTFE cannot be expected to show improvement in adhesive strength because it is a degradation-prone polymer and surface fatigue is produced by ion irradiation. We focused on cross-linked structure to solve this problem. PTFE was changed from a degradation-prone polymer into a cross-linked polymer by raising the temperature above the glass-transition temperature during ion irradiation. As a result, the formation of CF3 bonds was inhibited and degradation was prevented by ion irradiation above the glass-transition temperature. In addition, combined consideration of the C1s spectrum and the density profile suggests that a cross-linked structure is effective for improvement of adhesive strength. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(4): 1-7, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.21225 [ABSTRACT FROM AUTHOR]

It is reported that metastable excited particles affect the breakdown properties of nitrogen gas under low pressure extended over a long period. The purpose of this study is to confirm the influence of excited particles with the high-pressure condition and to reduce the influence by excited particles. In the experiment, the delay time was measured and the number of primary electrons was evaluated. The test was carried out in N2/NO, N2/CO, N3/SP6, and N2/NO/SF6. The decrease rate of the primary electron number supplied by excited particles is higher in N2/NO than in N2/CO2. In N2/NO/SF6, it was more effective than two mixture gases. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(3): 1–7, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20939 [ABSTRACT FROM AUTHOR]