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Ultra-stretchable hydrogel thermocouples for intelligent wearables

超拉伸水凝胶热电偶

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Abstract

Stretchable temperature sensors are necessary to enable tactile interaction and thermoregulation in the human body and soft robots. These sensors should be conformably adhered to a deformable surface and maintain temperature perception accuracy when stretched. However, current mainstream stretchable temperature sensors based on thermistors suffer from inherently unstable sensing during stretching due to the mutual interference of resistance changes caused by temperature and mechanical deformations. Herein, we propose an ultra-stretchable hydrogel thermocouple that provides unaltered temperature sensing upon stretching. The ultrastretchability of this thermocouple is achieved by constructing thermogalvanic hydrogels with dynamic crosslinked double networks. By connecting P-type and N-type thermogalvanic hydrogels, the thermocouple exhibits a high equivalent See-beck coefficient of 1.93 mV K−1 and a stable sensitivity even under a 100% tensile strain. The advantage of this ultra-stretchable thermocouple is demonstrated in a smart glove prototype, which enables haptic feedback. Our work provides a new strategy for stretchable temperature sensors and may promote the development of intelligent wearables.

摘要

可拉伸温度传感对实现人机触觉交互和温度调节至关重要, 这 些传感元件需要贴合特异性表面, 且在拉伸条件下保持温度感知的精 度. 现有可拉伸温度传感器由于温度和形变引起电阻变化的相互干扰, 在拉伸过程中存在固有的传感不稳定问题. 本文提出了一种超可拉伸 水凝胶热电偶, 通过构建具有动态交联双网络的热电水凝胶, 实现水凝 胶热电偶的超拉伸性. 通过设计的P型和N型热电水凝胶, 构建热电偶 单元. 热电偶表现出1.93 mV K−1的高塞贝克系数, 即使在100%的拉伸 应变下, 灵敏度依然保持稳定. 本文的研究结果为可拉伸温度传感器提 供了一种新的策略, 并有望广泛应用于智能可穿戴设备.

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (62161160311, 22209124 and 51976141), the Natural Science Foundation of Hubei Province (2021CFB208), and the Science and Technology Development Fund, Macao SAR (FDCT) (0059/2021/AFJ and 0040/2021/A1).

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  1. These authors contributed equally to this work.

Authors and Affiliations

  1. MOE Key Laboratory of Hydraulic Machinery Transients, School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China

    Yifan Zhao  (赵乙凡), Xifan Fu  (付希凡), Binghan Liu  (刘冰涵), Zihan Zhuang  (庄子涵) & Kang Liu  (刘抗)

  2. School of Smart Manufacturing, Jianghan University, Wuhan, 430056, China

    Jiantao Sun  (孙剑韬)

  3. The Institute of Technological Sciences, Wuhan University, Wuhan, 430072, China

    Peihua Yang  (杨培华)

  4. Department of Electromechanical Engineering and Centre for Artificial Intelligence and Robotics, University of Macau, Macao, 999078, China

    Junwen Zhong  (钟俊文)

Authors
  1. Yifan Zhao  (赵乙凡)
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  2. Xifan Fu  (付希凡)
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  6. Peihua Yang  (杨培华)
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  7. Junwen Zhong  (钟俊文)
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  8. Kang Liu  (刘抗)
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Contributions

Zhao Y carried out the material preparation, measurement platform construction and device test. Fu X provided experimental ideas and wrote the manuscript. Liu B participated in material preparation and graphics drawing. Sun J provided demonstration plans. Zhuang Z carried out the data analysis. Liu K, Yang P, and Zhong J provided the overall concept, supervised the project and revised the manuscript. All authors contributed to the general discussion.

Corresponding authors

Correspondence to Peihua Yang  (杨培华), Junwen Zhong  (钟俊文) or Kang Liu  (刘抗).

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Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary information

Supporting data are available in the online version of the paper.

Yifan Zhao received her Bachelor’s degree from Wuhan University in 2021. She is currently a Master’s student under the supervision of Prof. Kang Liu at Wuhan University. Her research interests focus on the development of flexible electronic devices and advanced tactile sensing technology.

Xifan Fu received his Bachelor’s degree from Wuhan University in 2019. Now he is a PhD student under the supervision of Prof. Kang Liu at Wuhan University. His research focuses on flexible tactile sensors and actuators.

Kang Liu received his Bachelor’s degree (2009) and PhD degree (2014) in thermal engineering from Wuhan University, China. Then, he worked at Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), as a research scientist. During 2017–2018, he was a visiting professor at Stanford University. He joined the School of Power and Mechanical Engineering at Wuhan University as a professor at the end of 2018. His main research interest is advanced thermo-fluidics for energy applications.

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Zhao, Y., Fu, X., Liu, B. et al. Ultra-stretchable hydrogel thermocouples for intelligent wearables. Sci. China Mater. 66, 1934–1940 (2023). https://doi.org/10.1007/s40843-022-2300-3

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  • DOI: https://doi.org/10.1007/s40843-022-2300-3

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