Mechanical Properties and Processing Techniques of Bulk Metal-Organic Framework Glasses

22 October 2018, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Glasses formed by melt quenching metal–organic frameworks (MOFs) are attracting growing attention because they exhibit an improved processability compared with their crystalline counterparts. Melt quenched MOF glasses also define a new category of glass, distinct from metallic, organic and inorganic glasses, owning to the role that metal-ligand coordination bonding plays in their three-dimensional structures. The mechanical properties of glasses in general are of importance given their application in protective coatings, display technologies and screens. Little, however, is known about the mechanical behavior of MOF-glasses, and 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): agZIF-4, agZIF-62, agZIF-76 and agZIF-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. One glass, agZIF-62, was used to explore two strategies for the preparation of bulk glass samples, i.e. (i) vacuum hot-pressing and (ii) remelting and annealing. Vacuum hot-pressing 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 a MOF-glass. The results are of high significance for potential applications of MOF-glasses.


metal organic framework
scratch testing

Supplementary materials

Supp Info Mechanical Properties and Bulk MOF Glasses


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.