Elucidation of the initial process of bubble nucleation by nanoscale three-dimensional measurements of solid-liquid interfaces during heating

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20405
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
• Research Institution: Kyushu University
• Principal Investigator: Teshima Hideaki 九州大学, 工学研究院, 助教 (60906220)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 接触線ピニング / ナノ液滴 / 原子間力顕微鏡 / 凝縮 / 蒸発 / ナノ計測 / 固液界面

Outline of Final Research Achievements

The phase transition from liquid to vapor allows for highly efficient cooling; however, the initial stages of this process cannot be observed using optical microscopes due to insufficient resolution, leaving many mysteries unanswered. This research aimed to gain new insights by observing solid-liquid interface during heating at the nanoscale using atomic force microscopy. As a result, we revealed that surface roughness of approximately 0.2 nm, which is negligible at the macroscale, acts as a powerful pinning site for the nanoscale fluid. We also conducted research in parallel using transmission electron microscopy and molecular dynamics simulations, obtaining valuable insights into nanoscale droplets and bubbles.

Free Research Field

界面工学

Academic Significance and Societal Importance of the Research Achievements

沸騰現象の最初期に関連するナノバブルが安定して存在するには強力な接触線ピニングが必要である一方、なぜ平坦な面においてピニングが生じるのかこれまで明らかでなかった。その理由が原子レベルの表面粗さに起因することを明らかにした本研究成果は、発泡初期過程の解明に資する重要な知見である。
また本成果は沸騰現象やナノバブルだけでなく、将来のナノ流路設計やその内部での流動現象の理解においても基盤的知見となる。