Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes

Authors

Xiuxiu Guo, Nankai University
Tianhui Mao, Nankai University
Zhifang Wang, Nankai University
Peng Cheng, Nankai University
Yao Chen, Nankai University
Shengqian Ma, University of South FloridaFollow
Zhenjie Zhang, Nankai University

Document Type

Article

Publication Date

2020

Digital Object Identifier (DOI)

https://doi.org/10.1021/acscentsci.0c00260

Abstract

Seeking new photoresponsive materials with high energy conversion efficiency, good mechanical properties, as well as well-defined photoactuation mechanisms is of paramount significance. To address these challenges, we first introduced crystalline covalent organic frameworks (COFs) into the photoactuator field and created a facile fabrication strategy to directly install photoresponsive functional groups (i.e., acylhydrazone) on the skeletons of COFs. Herein, an approach to use polyethylene glycol (PEG) cross-linked dimers as the building blocks of the COF-42 platform was developed and afforded a series of uniform and freestanding membranes (PEG-COF-42) with outstanding mechanical properties (e.g., high flexibility and mechanical strength). Notably, these membranes possessed a fast mechanical response (e.g., bending) to UV light and good reversibility upon blue light or heating. After an in-depth investigation of the photoactuation mechanism via various techniques, we proposed a mechanism for the photoresponsive performance of PEG-COF-42: configurational change of acylhydrazone (i.e., E ↔ Z isomerization) accompanied by an excited-state intramolecular proton transfer (ESIPT) process intramolecularly transferring hydrogens from hydrogen donors (N—H) to hydrogen acceptors (oxygen in PEG). Moreover, attributed to the PEG moieties, PEG-COF-42 also demonstrated a vapor-responsive performance. This study not only broadens the application scopes of COFs but also provides new opportunities for the construction of multi-stimuli-responsive materials.

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Citation / Publisher Attribution

ACS Central Science, v. 6, issue 5, p. 787-794

This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

Scholar Commons Citation

Guo, Xiuxiu; Mao, Tianhui; Wang, Zhifang; Cheng, Peng; Chen, Yao; Ma, Shengqian; and Zhang, Zhenjie, "Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes" (2020). Chemistry Faculty Publications. 114.
https://digitalcommons.usf.edu/chm_facpub/114