Measurement of surface tension change at the liquid interface in contact with plasma

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03596
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 14030:Applied plasma science-related
• Research Institution: Hokkaido University
• Principal Investigator: Shirai Naoki 北海道大学, 工学研究院, 准教授 (80552281)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 大気圧プラズマ / 表面張力 / 気液界面プラズマ

Outline of Final Research Achievements

The plasma-liquid interface is highly chemically reactive, however, the reactive species and radicals that contribute to the reaction are short-lived, and their measurement has not progressed much. In this study, we focused on the surface tension of the liquid and investigated how it is changed by plasma. Since the surface tension is determined by van der Waals forces and hydrogen bonds between molecules, reactive species and radicals transported by atmospheric pressure plasma may affect the change in surface tension. We first established a means of measuring the surface tension of water interacting with plasma and confirmed that the surface tension value of water increased when it was irradiated with plasma. It was confirmed that the surface tension value of water increased when it was irradiated with plasma. It was clarified that the cause of the increase may be the substances produced by OH radicals.

Free Research Field

プラズマ応用

Academic Significance and Societal Importance of the Research Achievements

プラズマが液体と接した際に生じる界面現象について、表面張力というパラメータに着目したことは世界に先駆けた取り組みである。また実際にプラズマが接すると表面張力が増加するという予想に反した結果が得られたが、これはプラズマによるラジカル等の影響で分子の配向等が変化した可能性があり、今後この成果を発展させることでこれまで原理は十分に理解されずに応用事例が先行していたプラズマ液体界面の相互作用において、学術的理解を得ることが可能になる。