Observation of indentation-induced shear bands in a metal−organic framework glass

Malwina Stepniewska, Kacper Januchta, Chao Zhou, Ang Qiao, Morten Mattrup Smedskjær, Yuanzheng Yue

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Abstrakt

Metal-organic framework (MOF) glasses are a newly emerged family of melt-quenched glasses. Recently, several intriguing features, such as ultrahigh glass-forming ability and low liquid fragility, have been discovered in a number of zeolitic imidazolate frameworks (ZIFs) that are a subset of MOFs. However, the fracture behavior of ZIF glasses has not been explored. Here we report an observation of both cracking pattern and shear bands induced by indentation in a representative melt-quenched ZIF glass, that is, ZIF-62 glass (ZnIm1.68bIm0.32). The shear banding in the ZIF glass is in strong contrast to the cracking behavior of other types of fully polymerized glasses, which do not exhibit any shear bands under indentation. We attribute this anomalous cracking behavior to the easy breakage of the coordinative bonds (Zn-N) in ZIF glasses, since these bonds are much weaker than the ionic and covalent bonds in network glasses.

OriginalsprogEngelsk
TidsskriftProceedings of the National Academy of Sciences of the United States of America
Vol/bind117
Udgave nummer19
Sider (fra-til)10149–10154
Antal sider6
ISSN0027-8424
DOI
StatusUdgivet - 12 maj 2020

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