Mechanical Properties and Processing Techniques of Bulk Metal-Organic Framework Glasses
Mechanical Properties and Processing Techniques of Bulk Metal-Organic Framework Glasses
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块状金属 - 有机框架玻璃的力学性能与加工工艺
DOI：
10.1021/jacs.8b11357
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发表时间：
2019-01-16
影响因子：
15
通讯作者：
Bennett, Thomas D.
中科院分区：
文献类型：
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作者：
Li, Shichun;Limbach, Rene;Bennett, Thomas D.
由于金属-配体配位键合的主导作用，熔融淬火金属-有机骨架（MOF）玻璃定义了一种新的玻璃类别，与金属、有机和无机玻璃不同。考虑到玻璃在保护涂层和显示技术中的应用，玻璃的机械性能通常很重要，尽管人们对 MOF 玻璃在这方面知之甚少。由于缺乏能够生产大块玻璃样品的加工方法，对耐刮擦性等关键性能的实验阐明受到限制。在这里，使用纳米压痕技术研究了由沸石咪唑酯骨架（ZIF）形成的四种熔融淬火玻璃的杨氏模量和硬度：a（g）ZIF-4）a（g）ZIF-62，a（g）ZIF-76和a（g）ZIF-76-mbIm。通过应变率跳跃（SRJ）测试和恒定负载和保持（CLH）压痕蠕变实验研究了熔融淬火玻璃的抗蠕变性。研究发现应变率灵敏度值与其他玻璃状聚合物和富硒 GeSe 硫族化物玻璃的值接近。 a(g)ZIF-62 的真空热压导致含有玻璃和非晶态非熔融淬火 aZIF-62 的不均匀本体样品。然而，重熔和退火导致制造出透明、无气泡的块状样品，从而可以在 MOF 玻璃上进行首次划痕测试实验。
Melt quenched metal-organic framework (MOF) glasses define a new category of glass, distinct from metallic, organic, and inorganic glasses, owing to the dominant role of metal-ligand coordination bonding. The mechanical properties of glasses in general are important given their application in protective coatings and display technologies, though little is known about MOF glasses in this respect. The experimental elucidation of key properties such as their scratch resistance has been limited by the lack of processing methodologies capable of producing bulk glass samples. Here, nanoindentation was used to investigate the Young's modulus and hardness of four melt-quenched glasses formed from zeolitic imidazolate frameworks (ZIF): a(g)ZIF-4) a(g)ZIF-62, a(g)ZIF-76, and a(g)ZIF-76-mbIm. The creep resistance of the melt-quenched glasses was studied via strain-rate jump (SRJ) tests and through constant load and hold (CLH) indentation creep experiments. Values for the strain-rate sensitivity were found to be close to those for other glassy polymers and Se-rich GeSe chalcogenide glasses. Vacuum hot-pressing of a(g)ZIF-62 resulted in an inhomogeneous bulk sample containing the glass and amorphous non-melt-quenched aZIF-62. Remelting and annealing, however, resulted in the fabrication of a transparent, bubble-free bulk specimen, which allowed the first scratch testing experiments to be performed on an MOF glass.