Graphene Actuator With Bionic Slippery Surface

In recent years,the technology of intelligent robots with high autonomy,adaptability and reliability have aroused people’s wide interests.As a key part of the intelligent robots to complete the operation tasks,intelligent actuators have been widely studied.In order to solve the problems that common bilayer or multilayer graphenebased actuators are easy to fall off in the long-term deformation process and the function of the surfaces are single,here we propose to take use of femtosecond laser to fabricate the laser reduced graphene oxide(LRGO)actuator with bionic slippery surface and a series of bionic actuators which can be used for droplet collecting and transporting.Furthermore,the droplet signal detection function is introduced to our bionic actuators to realize the sensing of droplets.The details are as follows:1.The graphene oxide(GO)films prepared by vacuum filtration are reduced and structured by femtosecond laser direct writing technology.Micro/nano structures similar to the structure of Nepenthes are successfully prepared on the GO films,and the LRGO/GO films are obtained.Then we inject lubricating oil into the side of LRGO to form a lubricating layer.The oil can be stably adsorbed in the micro/nano structure of LRGO due to capillary force,thus oil-LRGO/GO film with bionic slippery surface is obtained.Then we analyze the surface structure and chemical element composition of both sides of the LRGO/GO film.LRGO side is full of micro/nano porous structures,and the oxygen content is significantly reduced.The slippery surface of oil-LRGO/GO film is characterized and analyzed either,and the results prove that we have successfully introduced a slippery surface with good smooth performance into LRGO/GO film.2.The humidity response performance of oil-LRGO/GO actuator,including humidity bending curvature,response/recovery time and long-term stability,is analyzed and studied.We find that the injection of lubricating oil not only will it not affect the flexibility of the actuator,but strengthen its humidity response performance because the existence of lubricating layer insulates the actuator from air better.The oilLRGO/GO actuator shows larger bending curvature,faster response/recovery time and better long-term stability compared with LRGO/GO actuator.The oil-LRGO/GO actuator can be used to prepare bionic petal and bionic frog tongue actuator with humidity responsibility.Besides,we take use of the bending performance and slippery surface of oil-LRGO/GO actuator to fabricate bionic fly trap actuator,which could be used for droplets collection and transportation.Furthermore,inspired from triboelectric power generator,droplet signal detection function is introduced into the actuator,which can complete the signal detection while collecting and transporting droplets and realize the sensing of droplets.To sum up,femtosecond laser direct writing technology is used to reduce GO film and make it structured synchronously.Then oil-LRGO/GO actuator combines humidity responsibility and bionic slippery surface,realizing humidity response deformation and the collection and transportation of droplets.Moreover,the electrical signals generated by droplets sliding can be regarded as a sensing signal of the sliding droplets.The oilLRGO/GO actuator has huge potential in microfluidics,droplet directional transporting and provides a new solution for the realization of multi-functional intelligent execution system and intelligent robots.