ABSTRACT
The systematicness, flexibility, and complexity of natural biological organisms are a constant stream of inspiration for researchers. Therefore, mimicking the natural intelligence system to develop microrobotics has attracted broad interests. However, developing a multifunctional device for various application scenarios has great challenges. Herein, we present a bionic multifunctional actuation deviceâa light-driven mudskipper-like actuator that is composed of a porous silicone elastomer and graphene oxide. The actuator exhibits a reversible and well-integrated response to near-infrared (NIR) light due to the photothermal-induced contractile stress in the actuation film, which promotes generation of cyclical and rapid locomotion upon NIR light being switched on and off, such as bending in air and crawling in liquid. Furthermore, through rational device design and modulation of light, the mechanically versatile device can float and swim controllably following a predesigned route at the liquid/air interface. More interestingly, the actuator can jump from liquid medium to air with an extremely short response time (400 ms), a maximum speed of 2 m s-1, and a height of 14.3 cm under the stimulation of near-infrared light. The present work possesses great potential in the applications of bioinspired actuators in various fields, such as microrobots, sensors, and locomotion.
Subject(s)
Biomimetics , Robotics , Infrared Rays , Locomotion , SwimmingABSTRACT
The actuation phenomena of materials upon external stimulus have attracted much attention for the development of excellent sensors and devices. Herein, we present a smart Janus-faced film that exhibits novel behavior of reverse orthogonal actuation under high humidity and a positive actuation under low humidity, which is achieved by asymmetric polymer brushes on polydimethysiloxane as a substrate through surface-initiated atom transfer radical polymerization. The classical theory of plates and shells and finite element simulations are also applied to understand the orthogonal actuation mechanism of the actuator. This Janus-faced film can reversely grab objects rapidly under high humidity, which provides significant potential to design a more intelligent actuator. In addition, this film is highly sensitive to humidity that even the approaching finger can make it to bend, which is just like the actuation behavior of Mimosa pudica. Based on the above phenomena, we also design the sensing devices to realize the detection of humidity. Interestingly, the film intelligently identifies different solvents (e.g., water and ethanol). This work may demonstrate significant potential in smart surface modifications, flexible robots, bionic sensors, and other fields.
