Content of research

Plasmas generated in liquid are of great interest in the fields of nanotechnology, environmental engineering and medical engineering, but the need for high voltage to generate the plasma can be an obstacle. Meanwhile, in the field of ultrasonic engineering, it is known that the interior of a bubble becomes plasma at the same time as the collapse of acoustic cavitation. Using a very simple method of inserting a perforated metal plate into a liquid where ultrasonic waves are applied, we have succeeded in localizing and efficiently generating acoustic cavitation, which is difficult to fix in position. This has been valued as a unique method of generating plasma in liquid without using high voltage. Currently, we are working to clarify the mechanism of this method and to prepare guidelines for the design of a large-scale device. In the future, we hope to develop various new plasma application technologies.

Potential for social implementation

• ・Increasing the efficiency of sonochemistry processes
• ・Preparation of metallic nanoparticles and nano colloids
• ・Application to cleaning technology
• ・Application to environmental purification technology
• ・Application to cell processing/sterilization technology
• ・Linkage with micro/nano bubble technology

Appealing points to industry and local governments

Although this technology is based on an accidental discovery and even its rationale is still unknown, we believe that it will help to improve the efficiency of conventional sonochemistry processes and that it can be applied to various in-liquid processing technologies. We’d like companies to propose methods for applying this technology so that we can conduct joint research to realize such applications.