Basic Characteristics for PEN Film Surface Modification Using Atmospheric-Pressure Nonequilibrium Microwave Plasma Jet

To understand the mechanism of surface processing using an atmospheric-pressure nonequilibrium microwave discharge plasma jet, we used optical emission spectroscopy to measure the vibrational and rotational temperatures of plasma. A microwave (2.45 GHz) power supply was used to excite the plasma. The vibrational and rotational temperatures in the plasma were measured at approximately 0.18 and 0.22 eV. We also conducted plasma surface processing of polyethylene naphthalate (PEN) film to measure changes in the water contact angle before and after the PEN film was processed and as the rotational temperature of the plasma increased. Analysis of all the results from XPS and surface free energy as calculated from the contact angle confirmed that an improvement in hydrophilic properties of the PEN film surface was produced by the microwave discharge plasma jet. We conclude that the hydrophilicity of the PEN film surface improves as the rotational temperature of the plasma increases. (C) 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(5): 42-49, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10207