Shape memory polymer with programmable recovery onset

Chujun Ni; Di Chen; Yu Yin; Xin Wen; Xiaolan Chen; Chen Yang; Guancong Chen; Zhuo Sun; Jihang Wen; Yurong Jiao; Chunyang Wang; Ning Wang; Xiangxing Kong; Shihong Deng; Youqing Shen; Rui Xiao; Xiuming Jin; Jun Li; Xueqian Kong; Qian Zhao; Tao Xie

doi:10.1038/s41586-023-06520-8

Shape memory polymer with programmable recovery onset

Nature. 2023 Oct;622(7984):748-753. doi: 10.1038/s41586-023-06520-8. Epub 2023 Sep 13.

Authors

Chujun Ni^#¹, Di Chen^#², Yu Yin³, Xin Wen¹, Xiaolan Chen¹, Chen Yang¹, Guancong Chen¹, Zhuo Sun¹, Jihang Wen^{4

5}, Yurong Jiao^{4

5}, Chunyang Wang⁶, Ning Wang⁶, Xiangxing Kong^{4

5}, Shihong Deng¹, Youqing Shen¹, Rui Xiao⁷, Xiuming Jin⁶, Jun Li^{4

5}, Xueqian Kong³, Qian Zhao⁸, Tao Xie^{9

10

11}

Affiliations

¹ State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China.
² Ningbo Innovation Center, Zhejiang University, Ningbo, China.
³ Department of Chemistry, Zhejiang University, Hangzhou, China.
⁴ Department of Colorectal Surgery and Oncology, Key Laboratory of Cancer Prevention and Intervention, Ministry of Education, Affiliated Second Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
⁵ Cancer Center, Zhejiang University, Hangzhou, China.
⁶ Eye Center, Affiliated Second Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
⁷ State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics, Zhejiang University, Hangzhou, China.
⁸ State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China. qianzhao@zju.edu.cn.
⁹ State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China. taoxie@zju.edu.cn.
¹⁰ Ningbo Innovation Center, Zhejiang University, Ningbo, China. taoxie@zju.edu.cn.
¹¹ Department of Colorectal Surgery and Oncology, Key Laboratory of Cancer Prevention and Intervention, Ministry of Education, Affiliated Second Hospital, School of Medicine, Zhejiang University, Hangzhou, China. taoxie@zju.edu.cn.

^# Contributed equally.

PMID: 37704734
DOI: 10.1038/s41586-023-06520-8

Abstract

Stimulus-responsive shape-shifting polymers^1-3 have shown unique promise in emerging applications, including soft robotics^4-7, medical devices⁸, aerospace structures⁹ and flexible electronics¹⁰. Their externally triggered shape-shifting behaviour offers on-demand controllability essential for many device applications. Ironically, accessing external triggers (for example, heating or light) under realistic scenarios has become the greatest bottleneck in demanding applications such as implantable medical devices⁸. Certain shape-shifting polymers rely on naturally present stimuli (for example, human body temperature for implantable devices)⁸ as triggers. Although they forgo the need for external stimulation, the ability to control recovery onset is also lost. Naturally triggered, yet actively controllable, shape-shifting behaviour is highly desirable but these two attributes are conflicting. Here we achieved this goal with a four-dimensional printable shape memory hydrogel that operates via phase separation, with its shape-shifting kinetics dominated by internal mass diffusion rather than by heat transport used for common shape memory polymers^8-11. This hydrogel can undergo shape transformation at natural ambient temperature, critically with a recovery onset delay. This delay is programmable by altering the degree of phase separation during device programming, which offers a unique mechanism for shape-shifting control. Our naturally triggered shape memory polymer with a tunable recovery onset markedly lowers the barrier for device implementation.