Self‐Healing, Adhesive, and Highly Stretchable Ionogel as a Strain Sensor for Extremely Large Deformation

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 15; no. 21; pp. e1804651 - n/a
• Main Authors: Zhang, Li Mei, He, Yuan, Cheng, Sibo, Sheng, Hao, Dai, Keren, Zheng, Wen Jiang, Wang, Mei Xiang, Chen, Zhen Shan, Chen, Yong Mei, Suo, Zhigang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-05-2019
• Subjects: adhesion; Adhesive strength; Automation; Deformation; Healing; ionogel nanocomposites; Iron oxides; Manufacturing engineering; Nanocomposites; Nanoparticles; Nanotechnology; Robotics; self‐healing; Sensors; strain sensors; Stretchability; ionogel nanocomposites; adhesion; strain sensors; stretchability; self-healing
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201804651

Fabricating a strain sensor that can detect large deformation over a curved object with a high sensitivity is crucial in wearable electronics, human/machine interfaces, and soft robotics. Herein, an ionogel nanocomposite is presented for this purpose. Tuning the composition of the ionogel nanocomposites allows the attainment of the best features, such as excellent self‐healing (>95% healing efficiency), strong adhesion (347.3 N m−1), high stretchability (2000%), and more than ten times change in resistance under stretching. Furthermore, the ionogel nanocomposite–based sensor exhibits good reliability and excellent durability after 500 cycles, as well as a large gauge factor of 20 when it is stretched under a strain of 800–1400%. Moreover, the nanocomposite can self‐heal under arduous conditions, such as a temperature as low as −20 °C and a temperature as high as 60 °C. All these merits are achieved mainly due to the integration of dynamic metal coordination bonds inside a loosely cross‐linked network of ionogel nanocomposite doped with Fe3O4 nanoparticles.
An ionogel nanocomposite with the combined features of excellent autonomous self‐healing, strong adhesion, high stretchability, and strain sensitivity is fabricated. A conformal strain sensor based on the nanocomposite is demonstrated by changing electrical resistance with special distortion, like arbitrary curved and moving surfaces of a balloon with large inflation. The proof‐of‐concept strain sensor holds great potential for exploring various conformal mechanical sensor systems.