Volume 18, Issue 2 2104440
Research Article

Precisely Defining Local Gradients of Stimuli-Responsive Hydrogels for Complex 2D-to-4D Shape Evolutions

Jincai Yin

Jincai Yin

College of Materials Science and Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological Textiles, Institute of Marine Bio-based Materials, Qingdao University, Qingdao, 266071 China

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Wenxin Fan

Corresponding Author

Wenxin Fan

College of Materials Science and Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological Textiles, Institute of Marine Bio-based Materials, Qingdao University, Qingdao, 266071 China

E-mail: [email protected]; [email protected]; [email protected]

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Zihan Xu

Zihan Xu

College of Materials Science and Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological Textiles, Institute of Marine Bio-based Materials, Qingdao University, Qingdao, 266071 China

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Jinghua Duan

Jinghua Duan

College of Materials Science and Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological Textiles, Institute of Marine Bio-based Materials, Qingdao University, Qingdao, 266071 China

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Yanzhi Xia

Yanzhi Xia

College of Materials Science and Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological Textiles, Institute of Marine Bio-based Materials, Qingdao University, Qingdao, 266071 China

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Zhihong Nie

Corresponding Author

Zhihong Nie

State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, 200438 China

E-mail: [email protected]; [email protected]; [email protected]

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Kunyan Sui

Corresponding Author

Kunyan Sui

College of Materials Science and Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Shandong Collaborative Innovation Center of Marine Biobased Fibers and Ecological Textiles, Institute of Marine Bio-based Materials, Qingdao University, Qingdao, 266071 China

E-mail: [email protected]; [email protected]; [email protected]

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First published: 05 November 2021
Citations: 15

Abstract

The intellectualization and complication of existing self-shaping materials are limited by the inseparable monotonic relationship between their deformation rate and deformation degree (i.e., a higher deformation rate is accompanied by a high deformation degree). This causes that they can only deform from 2D to 3D states. Here, a simple yet versatile strategy to decouple the monotonic correlation between the deformation rate and deformation degree of self-shaping hydrogels is presented for achieving complex deformations from 2D to temporary 3D to 3D (2D-to-4D). It is demonstrated that when the gradient hydrogels prepared by photopolymerization possess dense polymer networks, the local regions with a high deformation rate can exhibit a low deformation degree. The resulting hydrogels can thus deform in a novel 2D-to-4D mode under external stimuli. During the deformation, they first transform into the temporary shapes induced by the local deformation rate difference, and then transform into the final shapes determined by the local deformation degree difference. Through controlling the ultraviolet irradiation direction and time to precisely program the local gradients of self-shaping hydrogels, they can be designed to produce various unprecedented yet controllable 2D-to-4D shape evolutions on demand, such as transformable origami, sequential gesture actions in finger-guessing games, mobile octopuses, time switch, etc.

Conflict of Interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

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