Gas Temperature Effect on Reactive Species Generation from the Atmospheric Pressure Air Plasma Ho Young Kim, y Sung Kil Kang, y Hyoung Cheol Kwon, Hyun Woo Lee, Jae Koo Lee* 1. Introduction Interest in the biomedical applications of atmospheric pressure plasmas (APPs) is increasing rapidly. [1] It shows remarkable efficacy in the cancer cell treatment, [2,3] sterilization, [4,5] wound healing, [6] coagulation, [7] and tooth whitening. [8] Compared with the previous low-pressure plasma, APPs have advantages because they can be operated without a bulky vacuum pump with relatively low input power. Most APPs are non-thermal plasmas. High collisional characteristic of APPs causes their non- equilibrium property between electrons and ions, which enables hot electrons, cold neutral gas, and ions to co-exist. Energetic electrons enhance the generation of reactive radicals and ions, which are important factors on the bio- medical application of APPs, with plasma gas temperature kept low. [1] It facilitates the treatment of APPs on the thermal sensitive materials without causing thermal damage. In addition, APPs can be operated with a wide range of driving frequencies from dc (0 Hz) to microwave (approximately few GHz). [1] Moreover, the shape of APPs can be tuned, e.g., from narrow plasma needles to surface type devices. [1] In spite of these advantages, most APPs have limitation for portable device applications because APPs need a huge carrier gas cylinder. Argon and helium are preferred as carrier gases because of their low breakdown power. [9] To Full Paper H. Y. Kim, S. K. Kang, H. C. Kwon, J. K. Lee Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea Fax: þ82 54 279 2903; E-mail: jkl@postech.ac.kr H. W. Lee, J. K. Lee Medipl Corporation, Pohang 790-834, Republic of Korea y Both authors contributed equally to this work. Using surface type air atmospheric pressure plasma, we investigated the amount of ozone and other reactive species generation with variations of the surface temperature of an electrode through an optical emission spectrum and a tube type gas detector. Reduced version of global model (GM) was employed to complement these experimental observations. The results of the model matched well with the experimental data. The amount of ozone generated from the surface type air plasma device was dramatically reduced with increasing temperature. Atomic oxygen (O) and nitric oxide (NO) radicals, which are import- ant agents for biomedical applications, propor- tionally increased with increasing temperature. We also elucidated the dominant reaction related to the generation or loss of these radicals based on temperature variation through our GM. 686 Plasma Process. Polym. 2013, 10, 686–697 ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com DOI: 10.1002/ppap.201200163