Effects of O-2 Addition on the Discharge Parameters and Production of Reactive Species of a Transferred Atmospheric Pressure Plasma Jet

Author(s)

Nascimento, Fellype ^[1] ; Petroski, Kleber ^[1] ; Kostov, Konstantin ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, Fac Engn Guaratingueta, BR-12516410 Guaratingueta - Brazil

• Document type: Journal article
• Source: APPLIED SCIENCES-BASEL; v. 11, n. 14 JUL 2021.
• Web of Science Citations: 0

Abstract

The therapeutic effects of atmospheric pressure plasma jets (APPJs) have been associated with the presence of reactive species, mainly the reactive oxygen and nitrogen ones, generated in this kind of plasmas. Due to that, many studies attempting to enhance the production of reactive species in APPJs have been performed. The employment of gas admixtures, usually mixing a noble gas with oxygen (O-2) or water vapor, is one of the most common methods to achieve such goal. This work presents a study of how the addition of small amounts of O-2 affects the electrical parameters and the production of reactive species in a transferred APPJ produced at the tip of a long and flexible plastic tube. The study was carried out employing helium (He) as the working gas and applying a high voltage (HV) in the form of amplitude-modulated sine waveform (burst mode). With this configuration it was possible to verify that the O-2 addition reduces the discharge power and effective current, as a result of late ignition and shorter discharge duration. It was also found that the addition of O-2 to a certain content in the gas admixture makes the light emission from oxygen atoms increase, indicating an increment in oxygen related reactive species in the plasma jet. However, at the same time the light emitted from hydroxyl (OH) and nitric oxide (NO) exhibits the opposite behavior, i.e., decrease, indicating a reduction of such species in the APPJ. For these reasons, the addition of O-2 to the working gas seems to be useful for increasing the effectiveness of the plasma treatment only when the target modification effect is directly dependent on the content of atomic oxygen. (AU)

• FAPESP's process: 20/09481-5 - Applications of non-thermal atmospheric plasmas in Dentistry: from the bench to the clinic
• Grantee: Fellype do Nascimento
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/05856-7 - Use of low temperature atmospheric pressure plasma in dentistry: from laboratory bench to clinics
• Grantee: Cristiane Yumi Koga Ito
• Support Opportunities: Research Projects - Thematic Grants