Electrically and Sunlight‐Driven Actuator with Versatile Biomimetic Motions Based on Rolled Carbon Nanotube Bilayer Composite

Abstract

Designing multistimuli responsive soft actuators which can mimic advanced and sophisticated biological movements through simple configuration is highly demanded for the biomimetic robotics application. Here, inspired by the human's flick finger behavior which can release large force output, a soft jumping robot mimicking the gymnast's somersault is designed based on the rolled carbon nanotube/polymer bilayer composite actuator. This new type of rolled bilayer actuator with tubular shape is fabricated and shows electrically and sunlight‐induced actuation with remarkable performances including ultralarge deformation from tubular to flat (angel change >200° or curvature >2 cm−1), fast response (<5 s), and low actuation voltage (≤10 V). Besides jumping, the uniquely reversible rolling–unrolling actuation can lead to other smart soft robots with versatile complex biomimetic motions, including light‐induced tumbler with cyclic wobbling, electrically/light‐induced crawling‐type walking robots and grippers, electrically induced mouth movement, and ambient‐sunlight‐induced blooming of a biomimetic flower. These results open the way for using one simple type of actuator structure for the construction of various soft robots and devices toward practical biomimetic applications.

Soft Robotic Grippers

“…When developing stimuli‐responsive polymers and gels, researchers often demonstrate soft grippers as a potential application. Such materials have shown grasping in response to the application of various external stimuli including chemical (pH change, salt concentration, and solvent exposure), dissolution, humidity change, electrical, thermal, optical, and magnetic . Those stimuli triggered actuators exploit swelling, ion migration, oxidation, thermal expansion, phase transition, and field deformations.…”

Photoresponsive Actuators Built from Carbon‐Based Soft Materials

“…The coefficient of thermal expansion (CTE) is often used to evaluate the sensitivity of thermal expansion to temperature as an intrinsic property of materials. As is well known, carbon materials have relatively smaller CTEs compared with certain polymers such as poly(vinylidene fluoride) (PVDF), poly(dimethylsiloxane) (PDMS), and polycarbonate (PC) . When integrating CNTs and PDMS with different CTEs into an asymmetric bilayer structure, PDMS with a high CTE appreciably expands with increasing temperature, while the volume of CNTs have negligible or minor changes; therefore, a predictable deformation is generated.…”

Smart Devices Based on the Soft Actuator with Nafion-Polypropylene-PDMS/Graphite Multilayer Structure

“…Flexible smart actuators driven by these stimuli have significant advantages in the soft robot, electronic skin, bionic technology and other fields [17][18][19][20]. For example, inspired by the flicking finger motions for rapidly releasing elastic energy, a curled carbon nanotube (CNT)-polydimethylsiloxane (PDMS) bilayer composite film actuator was designed and fabricated to simulate gymnastics tumbling in the air under low voltage and light illumination [21]. The flexible material encapsulates the micro-fabricated gold skeleton to replicate the fish's morphology, driving the fish's swimming and steering with optical stimulation [22].…”