Wireless Monitoring of Small Strains in Intelligent Robots via a Joule Heating Effect in Stretchable Graphene–Polymer Nanocomposites

• Published in: Advanced functional materials 2020-03, Vol.30 (13), p.n/a
• Main Authors: Zhang, Ding, Xu, Suwen, Zhao, Xue, Qian, Weiqi, Bowen, Chris R., Yang, Ya
• Format: Article
• Language: English
• Subjects: Automation; Environmental monitoring; Graphene; graphene–polymer; High temperature effects; joule heating effects; Manufacturing engineering; Materials science; Nanocomposites; Ohmic dissipation; Polymers; Resistance heating; Robotics; Robots; Sensors; strain sensors; stretchable sensors; Surface structure; wireless monitoring; Working conditions
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201910809

Flexible strain sensors are an important component for future intelligent robotics. However, the majority of current strain sensors must be electrically connected to a corresponding monitoring system via conducting wires, which increases system complexity and restricts the working environment for monitoring strains. Here, stretchable graphene–polymer nanocomposites that act as strain sensors using a Joule heating effect are reported. When the resistance of the sensor changes in response to a strain, the resulting change in temperature is wirelessly detected in an intelligent robot. By engineering and optimizing the surface structure of graphene–polymer nanocomposites, the fabricated strain sensors exhibit excellent stability when subjected to periodic temperature signals over 400 cycles while being periodically strained and deliver a high strain sensitivity of 7.03 × 10−4 °C−1 %−1 for strain levels of 0% to 30%. As a wearable electronic device, the approach provides the capability to wirelessly monitor small strains for intelligent robots at a high strain resolution of ≈0.1%. Moreover, when the strain sensing system operates as a multichannel structure, it allows precise strain detection simultaneously, or in sequence, for each finger of an intelligent robot. A multichannel strain sensor system can precisely realize strain detection of individual fingers of an intelligent robot in real time with an ultrahigh strain resolution of ≈0.1%.