A Closed-Loop Recyclable Hydrogel With Temperature-Programmable Photomorphing Enabled by a Dynamic
Chang Liu1, Hanren Xu1, Minyi Ma1
1Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China.
This study introduces a novel dynamic covalent hydrogel capable of temperature-controlled light-induced shape changes (photomorphing) and closed-loop recycling. This sustainable soft material offers advanced functionality and end-of-life circularity for future soft actuators.
Area of Science:
- Soft Matter Science
- Materials Chemistry
- Polymer Science
Background:
- Integrating programmable actuation with material circularity is a key challenge for sustainable soft materials.
- Existing soft actuators often lack recyclability, leading to environmental concerns.
Purpose of the Study:
- To develop a single material platform that combines temperature-programmable photomorphing with closed-loop recyclability.
- To investigate the synergistic effects of molecular isomerization and phase transitions in dynamic covalent networks.
Main Methods:
- Synthesized a dynamic covalent hydrogel using spiropyran-modified thioctic acid, oligo(ethylene glycol)-modified thioctic acid, and a dithiolane crosslinker.
- Utilized visible-light irradiation at different temperatures to induce distinct photomorphing behaviors.
- Investigated material recyclability through mild basic depolymerization.
Main Results:
- Achieved temperature-programmable photomorphing (bending and recovery, or fast bending without recovery) via visible-light irradiation.
- Demonstrated stable photomorphing function for up to three weeks under various storage conditions.
- Obtained up to 95% recovery of the spiropyran-modified monomer, establishing a closed-loop lifecycle.
Conclusions:
- The developed hydrogel offers a promising strategy for sustainable soft actuators with both advanced functionality and end-of-life circularity.
- The interplay between spiropyran photoisomerization and LCST-driven phase transitions is crucial for temperature-programmable photomorphing.
- This work advances the design of recyclable soft materials for future applications.
