Flexible Strain-Sensing Electronic Skin with Anisotropic Conductive Properties
Lang Bo1, Zhang Xuehui2, Wu Xiaogang1, Wang Yanqin1,3#*, Chen Weiyi1
1(College of Biomedical Engineering,Taiyuan University of Technology, Taiyuan 030024, China) 2(College of Materials Science and Engineering,Taiyuan University of Technology, Taiyuan 030024, China) 3(Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Taiyuan 030024, China)
Abstract：Electronic skins (e-skins) with intelligent sensing abilities for physiological signals have attracted much attention for their promising applications in smart robots, human-machine interfaces, and wearable medical systems. It is crucial to construct e-skins with anisotropic conductive properties to broaden the application scope of flexible sensing e-skins. In this work, a kind of composite hydrogel named Fe3O4@MXene/PVA with anisotropic conductive properties was constructed by using flexible polyvinyl alcohol (PVA) as hydrogel matrix. Magnetic induction technology was used to induce the orientation alignment of Fe3O4@MXene in the PVA hydrogel. Experimental results showed that when the cross-linking degree of PVA was 1.5% and the mass fraction of PVA was 8 wt%, the tensile modulus of Fe3O4@MXene/PVA reached 19.49 kPa and the fracture strain reached 237%. Mechanical properties of the resulted hydrogel were optimized. When the mass fraction of Fe3O4@MXene was 0.064 wt%, the electrical conductivity was optimal, the electrical conductivity in the direction parallel was 0.415 S/m and that in the perpendicular direction was 0.319 S/m. Finally, this work verified the feasibility of the composite hydrogel as an electronic skin for realizing real-time monitoring of the bending angle of human wrist joints. The anisotropic morphology and structure of the electronic are close to that of human tissues, and the composite hydrogel has broad application prospects in biomedical, electronic sensing, and other related fields.
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