Design And Manufacture Of MXene-based Flexible Actuator

With the development of Internet technology,a new generation of robots will be a coupling system composed of rigid material,flexible material,and moving mechanism,in which artificial muscles worked as one of the core components are expected to provide the functions of shape deformation,manipulation,and mobility.As one of the most common artificial muscles,electro-responsive electrochemical actuators consist of two flexible electrode layers and an electrolyte membrane sandwiched between the electrode layers.The main challenge in manufacturing an ionic actuator of large bending displacement and great response sensitivity is to design a flexible electrode with great electrochemical characteristic and conductivity.This research reports the MXene-PEDOT:PSS/Ag NWs electrode with a three-dimensional（3D）network layered structure formed by a hybrid method of the one-dimensional（1D）silver nanowires（Ag NWs）and the two-dimensional（2D）Ti₃C₂T_x MXene.The main research contents include the following aspects:（1）Preparation of MXene-PEDOT:PSS/Ag NWs composites.MXene nanosheets are very suitable as an electrode for actuators due to their ordered microstructures,tunable interlayer spaces,controllable electrochemical properties,and excellent electrical-mechanical properties.The optimal contents of PEDOT:PSS and Ag NWs were determined by measuring the nanosheet spacing,electrochemical properties,electrical conductivity and mechanical properties of the films.（2）Performance test of the ionic actuators.The experimental results show that the composite electrode greatly enhances the driving performance of the designed ionic soft actuator.Under a sinusoidal input voltage of±0.5V,the MPA electrode-based soft actuator achieves a large bending strain（0.48%）,wide frequency（0.1 Hz-10 Hz）,5-hour durability（91.9%retention）,the bending strain is 3.29 times higher than that of the actuator based on electrodes without the addition of Ag NWs.These excellent performances are mainly due to the excellent properties of Ti₃C₂T_x MXene and the 3D structure of the MXene-PEDOT:PSS/Ag NWs composite electrode.This study demonstrates that this 3D network layered hybrid electrode plays a significant role in enhancing the driving performance of artificial muscles.The oxygen-containing functional groups in MXene combined with PEDOT:PSS have good wettability and mechanical elasticity.The 3D structure formed by Ag NWs creates unhindered ion channels,which facilitates short diffusion and rapid injection of ions,and provides higher capacitance and mechanical integrity.（3）Biological applications of ionic actuators.The preparation of a grapple robot and a bionic butterfly to simulate the motion of rapidly grasping objects and the flapping of the butterfly wings reflects its great potential in exploring bionic devices.In conclusion,this 3D network layered structure hybrid electrode provides an opportunity for the development of ultralow voltage drivable artificial muscles.