Electron microscopic imaging of the solvation layer on nanoparticles

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15379
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 28010:Nanometer-scale chemistry-related
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: OKADA Satoshi 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(超先鋭研究開発プログラム), 研究員 (90780916)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 走査電子顕微鏡 / 極低温観察 / 含水試料

Outline of Final Research Achievements

The surface of solvent-dispersed nanoparticles is covered with solvents several nanometers in thickness. A Pickering emulsion is a biphasic particle whose interface is stabilized by surfactant nanoparticles, and the solvent layer should also exist in its inside, though not visualized so far. I tried to develop methods to visualize the inner-emulsion solvent layer using low-temperature scanning electron microscopy. Although the solvent layer was not clearly visualized, methods and tools to visualize it has been developed, including conductive adhesives operatable at dry ice to liquid nitrogen temperature, a system to measure the secondary electron emission coefficient of low-temperature samples in a microscopy chamber, and methods to expose inside of high-pressure frozen emulsions.

Free Research Field

物理有機化学

Academic Significance and Societal Importance of the Research Achievements

これまで極低温条件での走査電子顕微鏡観察には、試料の固定、導通の確保、像解釈などの問題が残っていたが、本研究を進める上で開発した技術により、これらの問題が部分的に解決され、今後の1 nmスケールでの生物・材料系試料の極低温走査電子顕微鏡観察に向けた基盤が確立された。また、化粧品等に用いられるエマルションの内部構造を可視化することに成功しており、本研究をさらに拡張することで有効成分の徐放などへの応用展開が期待される。