Graphene‐Based Actuator with Integrated‐Sensing Function

Abstract

Flexible actuators have important applications in artificial muscles, robotics, optical devices, and so on. However, most of the conventional actuators have only actuation function, lacking in real‐time sensing signal feedbacks. Here, to break the limitation and add functionality in conventional actuators, a graphene‐based actuator with integrated‐sensing function is reported, which avoids the dependence on image post‐processing for actuation detection and realizes real‐time measurement of the shape‐deformation amplitudes of the actuator. The actuator is able to show a large bending actuation (curvature of 1.1 cm−1) based on a dual‐mode actuation mechanism when it is driven by near infrared light. Meanwhile, the relative resistance change of the actuator is −17.5%. The sensing function is attributed to piezoresistivity and thermoresistivity of the reduced graphene oxide and paper composite. This actuator can be used as a strain sensor to monitor human motions. A smart gripper based on the actuators demonstrates perfect integration of the actuating and sensing functions, which can not only grasp and release an object, but also sense every actuation state of the actuator. The developed integrated‐sensing actuator is hopeful to open new application fields in soft robotics, artificial muscles, flexible wearable devices, and other integrated‐multifunctional devices.

Recent Advances in Photoactuators and Their Applications in Intelligent Bionic Movements

“…Owing to remote control and reversible deformation, photothermal actuators made of polymer and inorganic materials can be used as smart arms and grippers. [137][138][139] Zhao's group introduced Au nanorods in an LCPs containing Azo to fabricate two types of actuators: [98] one of these bent under UV light and returned to its initial shape under visible light stimuli whereas the other bent and generated a thermal contracting force upon NIR irradiation (Figure 8A). Thus, the group designed a smart arm and two grippers to grab/release and lift up/lower down objects with a weight-lifting ratio of 135 under light stimuli by utilizing these two types of actuators ( Figure 8B).…”

Photoresponsive Actuators Built from Carbon‐Based Soft Materials

“…By designing and preprogramming the light responsive actuator, the bilayer structures could offer a route to realize complex shape deformations. More recently, the same group demonstrated an integrated multifunctional device based on photoactuators by designing a layered actuator consisting of rGO, paper and biaxially oriented BOPP (rGO‐paper/BOPP) . During the photothermally induced bending process, the change in resistance of the actuator is determined by the strain and temperature dependence on the resistance of the RGO‐paper composite.…”

“…d) Relative resistance change and optical photos of the smart grippe in the process of grasping, raising up, and releasing an object. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…More recently, integrated light‐driven actuation systems have been widely studied due to multifunctionality or multiple stimuli responsiveness for smart practical applications. In Zhang's work, rGO/paper/biaxially oriented polypropylene (rGO‐Paper/BOPP) composite film combining the functions of actuation and sensing realized light‐driven shape deformation accompanied by real‐time feedback . The bending curvature, temperature and relative‐resistance change (resistance change/initial resistance (Δ R / R 0 ) were correlated; thus, ΔR/R 0 can be used to indicate the change in stress or curvature under NIR light irradiation (100 mW cm −2 ).…”

Light-Responsive Actuators Based on Graphene

“…LIG can form highly aligned structures, so that the bending direction is predictable and the actuator can achieve programmable complex shapes under light stimulus. Chen et al produced a graphene actuator with integrated-sensing function, whose shape changes will feedback real-timely (Chen et al, 2019). The reduced GO-paper (RGO-paper) in the actuator not only serves as an energy conversion material, but also functions as a sensing layer.…”