Dielectric Barrier Discharge in air for human skin treatment
Priyadarshini Rajasekaran, Nikita Bibinov, Peter Awakowicz
2nd International Workshop on Plasma-Tissue Interactions, 2.- 4.02.2009, Leibniz Institute for Plasma Science and Technology (INP Greifswald), Greifswald (Germany)
A dielectric barrier discharge (DBD) source with only one electrode covered with ceramic is characterized for effective use in skin therapy. A high capacitance object, like the human body, can serve as the opposite electrode. For characterization purpose, different opposite electrodes including metal, water, salt solution and glass are used and the discharge produced in each case is studied. Human skin conditions are very different. The aim of using different electrodes is to gain knowledge about the influence of the opposite electrode material and geometry, on the plasma properties. For this, the electrical and plasma parameters are determined for different opposite electrodes and compared with each other. The observations made for these opposite electrodes are used to optimize the discharge for application in dermatology like skin sterilization or skin healing. Optical Emission Spectroscopy (OES), Current-Voltage measurement, microphotography and plasma-chemical modeling are employed for plasma characterization. Plasma parameters like electron density (ne), reduced electric field (E/n), electron distribution function and gas temperature (Tg) are determined from the plasma physical processes. In addition, electrical parameters like ignition voltage (Vig), average plasma current and power dissipated in the production of photons, N2 and O2 ions and metastables, N and O atoms, nitric oxide, etc. in the plasma channel are calculated. Despite the high breakdown voltage in air at atmospheric pressure, the average current is observed to be low (<150 ?A) and hence the discharge is completely safe to be used in direct contact with human skin.