Exploring general nature of interfacial melting on ice crystals: in situ approach by optical microscopy

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01824
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 30010:Crystal engineering-related
• Research Institution: Hokkaido University
• Principal Investigator: Murata Kenichiro 北海道大学, 低温科学研究所, 助教 (60646272)
• Co-Investigator(Kenkyū-buntansha): 佐崎 元 北海道大学, 低温科学研究所, 教授 (60261509)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 氷の界面融解 / 擬似液体層 / 結晶成長 / 光学顕微鏡その場観察 / 不純物 / 潮解

Outline of Final Research Achievements

We focus on micro(nano)particles attached on ice crystal surfaces as a model of interfacial melting of ice crystals. We consider (i) roles of microparticles (or the interface between microparticles and ice crystal surfaces) for the generation of quasi-liquid layers (QLLs) and (ii) competition between microparticles and step dynamics on ice crystal surfaces. We reveal that microparticles are involved in the generation of QLLs through defects and dislocations induced by the microparticles themselves. We also demonstrate that surface elastic distortion, induced by the microparticles embedded in the ice crystal, affects the step dynamics.
In addition, we revisit deliquescence of sodium clorides to explore general nature of surface melting of ice crystals. We find similarities of wetting behavior between deliquescent liquid films and QLLs, which offer the possibility to understand the surface melting and the deliquescence in a unified manner.

Free Research Field

結晶成長学

Academic Significance and Societal Importance of the Research Achievements

本研究により，微粒子が結晶成長ダイナミクスや擬似液体層の生成に関与していることが明らかになった．本研究は特に上空での氷結晶とエアロゾルやブラックカーボンなどの不純物との関連を意識しているが，本成果を通じて，結晶成長学的視点から不純物を介した雲形成の新たな素過程を提示できる可能性がある．また，ごく最近，白金（111）面において，ステップが誘起する結晶表面の歪みが触媒活性を増強させるとの報告がある．本研究で示唆されるように，微粒子を介して結晶表面の歪みを制御できれば，触媒活性の更なる向上を狙った材料設計の可能性が開かれると考えられる．