分子内結晶による単成分均質液体における第二のガラス化
Ben A Russell1, Mario González-Jiménez1, Nikita V Tukachev1
1School of Chemistry, University of Glasgow, Glasgow G12 8QQ, U.K.
Journal of the American Chemical Society
|November 18, 2023
まとめ
純粋な液体には通常"つのガラスの変化がある. しかし,チタンテトラアルコシドは2つの特性を示し,1つは散発性であり,もう1つは分子内運動であり,液体-固体移行の従来の理解に挑戦しています.
科学分野:
- 物理化学
- 材料科学
- 凝縮物質物理学
背景:
- 超冷却液体によりガラス化が起こり,熱容量が低下した無形な固体を形成する.
- 純粋な均質な液体は,通常,単一のガラスの移行を示すことが期待されます.
- 従来のガラスの移行は,大量の液体の性質のダイナミックな停止を伴う.
研究 の 目的:
- 単一成分同質分子液体のガラスの移行行動を調査する.
- このようなシステムで複数のグラス・トランジションが起こるかどうかを判断する.
- タイタンテトラアルコシドで観察された明確なガラス変換の性質を明らかにする.
主な方法:
- カロリメトリック測定は,チタンテトラアルコシドの一族で行われた.
- 分析は,熱容量の明確な変化を特定し,特徴づけることに焦点を当てた.
- この研究は,熱現象と分子動力学と構造の変化を相関させた.
主要な成果:
- タイタンテトラアルコシドは,比較可能な大きさの2つのカロメトリック・グラス・トランジションを示す.
- 一つの移行は,従来の大量液体ダイナミック停止に対応します.
- 第2の移行は,分子内自由度の凍結に起因する.
結論:
- 同質な分子液体では,新種の分子内ガラスの現象が観察されました.
- これは,分子内運動が,質量特性に独立してガラスの移行を経験することを示唆しています.
- 分子内バリアを横断するプロセスは,常にアレニウスの行動に従っており,有限な温度で凍結することがあります.
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