Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes
| Autor: | Shengqian Ma, Zhifang Wang, Xiuxiu Guo, Tianhui Mao, Zhenjie Zhang, Peng Cheng, Yao Chen |
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| Rok vydání: | 2020 |
| Předmět: |
High energy
Materials science Fabrication 010405 organic chemistry General Chemical Engineering Energy conversion efficiency technology industry and agriculture Nanotechnology General Chemistry 010402 general chemistry 01 natural sciences 0104 chemical sciences Chemistry Membrane Artificial muscle QD1-999 Research Article Covalent organic framework |
| Zdroj: | ACS Central Science, Vol 6, Iss 5, Pp 787-794 (2020) ACS Central Science |
| ISSN: | 2374-7951 2374-7943 |
| Popis: | 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. We created a new class of smart COFs, PEG-COFs, which possess high crystallinity and mechanical properties, and exhibit a photomechanical property and vapor-triggered artificial muscle performance. |
| Databáze: | OpenAIRE |
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