The mechanism of structural phase transitions in organic crystals accompanied by crystal crushing and their device applications

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05045
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: National Institute for Materials Science
• Principal Investigator: TAKAZAWA Ken 国立研究開発法人物質・材料研究機構, 電子・光機能材料研究センター, 主幹研究員 (10354317)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 有機結晶 / 構造相転移 / ナノファイバー / アクチュエータ / ラマン分光 / 座屈 / 高速度カメラ

Outline of Final Research Achievements

It has been reported that some organic crystals suddenly break due to temperature-induced structural phase transitions. The development of molecular actuators with superior power by deriving mechanical work from such phase transitions is a fascinating concept. Here, we demonstrated that single crystal nanofibers of 1, 2, 4, 5-tetrabromobenzene, whose bulk crystals exhibit a sudden break, can repeatedly transform between the low and high temperature polymorphs without disintegration. Moreover, we constructed actuators using bending of nanofibers induced by the phase transition. We estimated the force generated by the actuator and found that it can generate a force large enough to flick an object 10,000 times heavier than the fiber itself into the air against gravity.

Free Research Field

分光学

Academic Significance and Societal Importance of the Research Achievements

温度変化や光照射などの外部刺激が誘起する有機結晶の構造相転移は、基礎科学とデバイス応用の両面から注目を集めている。中でも、構造相転移により粉砕を示す結晶は、現象の高速性と発生応力の大きさから、高速・高出力アクチュエータなどへの応用が期待されている。本研究では、粉砕を伴う相転移のダイナミクス研究を可能にする手法を開発しただけでなく、デバイス応用の可能性も実証した。従って、基礎科学とデバイス応用の両面で、波及効果・発展性が期待できる。