Abstract
<h2>Summary</h2> Two-dimensional (2D) covalent organic frameworks (COFs) are promising polymeric crystalline nanomaterials with broad applications. However, the understanding of their mechanical properties and fracture mechanisms remains elusive. Here, we report a quantitative <i>in situ</i> tensile study of ultrathin COF<sub>TAPB-DHTA</sub> films. The fracture strength was measured to be 0.75 ± 0.34 GPa, and the tensile modulus was measured to be 10.38 ± 3.42 GPa, with a nominal density of 0.393 g/cc, thus having specific strength equivalent to Kevlar (2 GPa·cc/g), and specific modulus comparable with titanium alloys (23 GPa·cc/g). In addition, the fracture toughness was measured to be 0.55 ± 0.09 MPa√m, and it was found that the crack propagation could be insensitive to the pre-crack when the size of pre-crack is below a critical value, leading to intriguing flaw insensitivity in such ultrathin nanomaterials. This work provides in-depth insights into the fracture properties of 2D COF films and lays a foundation for their future applications.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
