Study on Ice crystal growth mechanism through observation of hydration layers in quasi-liquid layer by high-speed FM-AFM

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20506
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0402:Nano/micro science, applied condensed matter physics, applied physics and engineering, and related fields
• Research Institution: Ryukoku University
• Principal Investigator: Miyato Yuji 龍谷大学, 先端理工学部, 准教授 (80512780)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 原子間力顕微鏡 / 高速AFM / 雪氷結晶

Outline of Final Research Achievements

We have newly developed the high-speed atomic force microscope (HS-AFM), which realizes probe-scan using a quartz crystal resonator sensor as a force sensor. The equipment design employs mechanics performing the less mechanical drift when the temperature changes. The controllable band width of the new high-speed scanner is approximately 20 kHz, which achieves a required level for HS-AFM. We have also confirmed the assembled AFM controller can perform frequency-modulation AFM (FM-AFM). Unfortunately, our new HS-AFM system still requires fine-tuning for best performances. Then, we analyzed the ice-crystal measurement results taken by previous prototype HS-AFM system. We found that the quasi-liquid layer (QLL) existed on ice-crystals, and that the QLL played a key role of surface condition of ice-crystals. This results indicated that the QLL could affect ice-growth processes.
We will continuously measure the QLL by using our newly developed HS-AFM system.

Free Research Field

計測工学

Academic Significance and Societal Importance of the Research Achievements

高速AFMで雪氷結晶を観察できる装置はこれまで報告されておらず、水晶振動子センサを用いたプローブスキャン方式の高速AFMも研究実績は多くはない。上記装置を研究活動スタート支援のお蔭によって整備できたことは、雪氷結晶の観察にとどまらず、湿度や温度をコントロールして測定できる点で応用範囲が広いと考えている。特に、試料が水などで部分濡れしていても水晶振動子センサの適用により安定撮像できるという技術的な意義もある。今後、安定動作を達成し、様々な条件で雪氷結晶を測定できるようになり、擬似液体層の粘性と成長速度の相関を明らかにできれば、永らく謎であった雪氷結晶の成長機構の解明に寄与することが期待できる。