ORIGINAL PAPER Development of Atmospheric Pressure Low Temperature Surface Discharge Plasma Torch and Application to Polypropylene Surface Treatment Atsushi Kuwabara Æ Shin-ichi Kuroda Æ Hitoshi Kubota Received: 6 November 2007 / Accepted: 26 December 2007 / Published online: 7 March 2008 Ó Springer Science+Business Media, LLC 2008 Abstract We have finally succeeded in producing the plasma jet by use of the surface discharge plasma torch that can be expected to make larger the diameter of torch in the comparatively easy way. It can be checked that the active species in the jet obtained are different depending on the direction of connection, and also it was clearly found that much O and N 2 is included in them. Consequently, etching was confirmed at the position of 10 mm from the torch end in the surface treatment of polypropylene film, but etching was not confirmed at the position of 20 mm. Keywords Atmospheric-pressure plasma Á Low-temperature plasma Á Surface discharge Á Plasma jet Introduction The reforming of material surface and the formation of functional thin film by use of the atmospheric pressure low-temperature plasma are the important industrial technology, for which the intensive research is being pursued [1, 2]. We have developed atmospheric pressure DBD low-temperature plasma torch, and reported the characteristics of plasma jet that is produced by this plasma torch [3]. We tried to make larger the diameter of torch and make the dielectric flatter in order to extend the application of this plasma torch, but it was difficult to produce the stable and uniform plasma jet. Therefore, we paid attention to the corona torch which can be expected to be comparatively easy for such diversification. Ono et al. [4] reported that the steady and sharp plasma was produced with the DC voltage applied between the electrodes while entering the Ar–N 2 mixed gas, using the stainless pipe for the inner electrode. However, they did not examine the characteristics of torch in details at that time. Hereupon, we have developed the surface discharge plasma torch that this corona torch was improved, and produced the plasma jet by this torch. And then, we A. Kuwabara (&) Á S. Kuroda Á H. Kubota Department of Chemistry, Faculty of Engineering, Gunma University, Tenjin-cho 1-5-1, Kiryu, Gunma 376-8515, Japan e-mail: papermaster@mail.goo.ne.jp 123 Plasma Chem Plasma Process (2008) 28:263–271 DOI 10.1007/s11090-007-9118-7