Hydrogels have emerged as promising materials for the construction of skin-like mechanical sensors.The common design of hydrogel-based artificial skin requires a dielectric sandwiched between two hydrogel layers for capacitive sensing.However,such a planar configuration limits the sensitivity,stretchability and self-healing properties.Here,we report the design of single-layer composite hydrogels with bulk capacitive junctions as mechanical sensors.We engineer dielectric peptide-coated graphene(PCG)to serve as homogenously dispersed electric double layers in hydrogels.Any mechanical motions that alter the microscopic distributions of PCG in the hydrogels can significantly change the overall capacitance.We use peptide self-assembly to render strong yet dynamic interfacial interactions between the hydrogel network and graphene.The resulting hydrogels can be stretched up to 77 times their original length and self-heal in a few minutes.The devices can effectively sense strain and pressure in both air and aqueous environments,providing tremendous opportunities for next-generation iontronics.

Bin Xue;Hui Sheng;Yongqiang Li;Lan Li;Weishuai Di;Zhengyu Xu;Linjie Ma;Xin Wang;Haoting Jiang;Meng Qin;Zhibo Yan;Qing Jiang;Jun-Ming Liu;Wei Wang;Yi Cao

National laboratory of Solid State Microstructures,Department of Physics,Nanjing University,Nanjing 210093,China;State Key Laboratory of Pharmaceutical Biotechnology,Department of Sports Medicine and Adult Reconstructive Surgery,Drum Tower Hospital Affiliated to Medical School of Nanjing University,Nanjing 210008,China;Institute for Brain Sciences,Nanjing University,Nanjing 210093,China;Chemistry and Biomedicine Innovation Center,Nanjing University,Nanjing 210093,China

国家科学评论（英文版）

[1]Bin Xue;Hui Sheng;Yongqiang Li;Lan Li;Weishuai Di;Zhengyu Xu;Linjie Ma;Xin Wang;Haoting Jiang;Meng Qin;Zhibo Yan;Qing Jiang;Jun-Ming Liu;Wei Wang;Yi Cao-.Stretchable and self-healable hydrogel artificial skin)[J].国家科学评论（英文版）,2022(07):36-48

iontronics

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