Graphene-Based Bimorph Actuators with Dual-Response and Large-Deformation by a Simple Method

There is a high demand for the design of high-performance soft actuators with multi-stimuli response and easy fabrication. Here, soft bimorph actuators consisting of graphene and polypropylene are fabricated by the drop-coating of graphene film and subsequent adhesion of polypropylene on the graphene film. The fabrication method is simple, fast, and scalable, and this bimorph actuator exhibits optically and electrically induced actuation with large and reversible deformation (angle change >100 degrees), fast response (approximate to 8s), and low driving voltage (7V). The remarkable actuation performance is mainly attributed to the thermally induced expansion of the polypropylene film, bimorph structure, and the energy conversion property of the graphene. Because of the dual-responsiveness and large-deformation, this actuator can be used to construct diversely biomimetic devices with smart mechanical output. As an example, an artificial flower composed of four pieces of the actuator is fabricated to show optically and electrically driven blooming. These results open the way for using a simple method for the construction of soft actuators and smart devices toward practical biomimetic applications.