Self-Powered and Self-Healable Triboelectric Sensors for Soft Robotics Applications

The use of robots has been growing dramatically in recent years in applications ranging from industrial production management to automotive, healthcare and surgical operations. In this regard, there are ongoing efforts to develop soft functional materials for robotic applications, both for actuation as well as sensing. Triboelectric nanogenerators, capable of converting small-scale mechanical energy from the surrounding environment into electrical energy through triboelectrification and electrostatic induction, offer an attractive route towards developing self-powered sensors. In this work, we present the development of self-powered triboelectric sensors which possess self-healable properties that can be integrated onto a soft robotic gripper. The self-healable triboelectric layer consists of an Ecoflex-coated self-healable polydimethylsiloxane (SH-PDMS) polymer that can autonomously repair mechanical injury at room temperature and regain its functionality [1], while the soft robotic gripper is made of 3D printed shape-memory polymer that can be thermally actuated near ambient temperatures [2]. The triboelectric layer is further modified by incorporating 2D MXene in the Ecoflex-based composite film. The conductive MXene with fluoride surface termination is found to enhance the triboelectric properties of the triboelectric sensor. As an example, a highly stretchable triboelectric sensor is fabricated and attached to a glove worn on a prosthetic soft robotic hand in order to explore whether the sensor can differentiate between different materials that are contacted by the robotic hand during operation.

[1] “Tailoring of Self-Healable Polydimethylsiloxane Films for Mechanical Energy Harvesting”, K. Ghosh, A. Morgan, X. Garcia-Casas, S. Kar-Narayan, ACS Appl. Energy Mater. 7, 8185 (2024)

[2] “3D-printed photothermal-responsive shape-memory polymer for soft robotic applications”, K. Ghosh, S. Kar-Narayan, Chem. Commun. DOI: 10.1039/D4CC03549F (2024)