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在ZIF-62玻璃中实验证实了β放松及其结构起源

Si-Xu Peng¹, Ying-Ying Zhu¹, Gang Li²

¹College of Chemistry & Chemical Engineering, Hubei University, Wuhan, 430062, Hubei, China.

|July 13, 2023

概括

金属有机框架 (MOF) 首次揭示了眼镜中的二次β放松. 这项研究探讨了MOF玻璃放松动态,为玻璃过渡机制提供了新的见解.

科学领域:

材料科学材料科学材料科学
凝聚物质物理学凝聚物质物理学
化学工程是化学工程的重要组成部分.

背景情况:

了解玻璃放松对于材料性能至关重要,但机制仍然不清楚.
金属有机框架 (MOF) 为研究玻璃放松现象提供了新的平台.
二次β-放松是玻璃行为的一个关键但不太了解的方面.

研究的目的:

在一个代表性的MOF玻璃 (ZIF-62) 中研究二次β放松.
探索MOF眼镜中放松动态的结构起源和相关性.
建立一种新的方法来研究MOF材料中的玻璃/液体过渡.

主要方法:

粉末机械光谱学使用商业动态机械分析仪与定制安装.
分析α-和β-放松峰值,包括它们的宽度 (W) 和偏离时间-温度叠加.
核磁共振 (NMR) 用于观察结构变化和密度.

主要成果:

在MOF玻璃中 (ZIF-62) 第一次观察β放松,与α放松一起.
在已知的玻璃中,ZIF-62玻璃表现出明显的β放松,其特点是过多的翼和最大峰幅 (W).
在脆弱性,拉伸指数 (β) 和峰值宽度 (W) 之间发现了线性相关性,这表明放松动态的共同起源.

结论:

这项研究提供了令人信服的证据,证明MOF眼镜中的β放松与密度增加有关.
研究结果表明,MOF玻璃和传统玻璃制造商的放松现象具有共同的机械起源.
这项工作引入了一种有效的方法来探测MOF眼镜中的玻璃过渡动态,提高对等级放松的理解.

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