Effect of atmospheric-pressure plasma irradiation on the surface tension of water. (20th January 2022)

• Record Type: Journal Article
• Authors: Shirai, Naoki; Kaneko, Takuma; Takamura, Yuto; Sasaki, Koichi
• Is Part Of: Journal of physics. Volume 55:Number 15(2022)
• Publication Date: 2022-01-20
• Subjects: atmospheric pressure plasma -- surface tension -- plasmsa–liquid interaction -- atmospheric pressure plasma jet; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac48ad
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: We have shown that measuring the surface tension is a useful scheme to examine the plasma–liquid interface in real-time. The surface tension was measured using a method based on the dispersion relation of an acoustic capillary wave excited on the water surface. The surface tension gradually increased with time, when the water surface was irradiated with the outside region of the spatial afterglow of an atmospheric-pressure plasma. The Marangoni effect associated with the localized increase in the surface tension was observed during the plasma irradiation. The surface tension decreased after the termination of the discharge. A correlation was found between the transient decrease in the surface tension and the variation of the OH radical density in the gas phase. No increase in the surface tension was observed in the solution containing a trapping agent for liquid-phase OH radicals. These experimental results suggest that OH radicals act to increase the surface tension. However, the behavior of the surface tension cannot be explained perfectly by considering only the action of OH radicals.