Research On Ultrafast Solvent-Driven Flexible Actuators With Sandwich Structure

Inspired by the movement phenomenon of biological response in nature,the design of bionic intelligent robots has emerged over the past decades.A variety of new biomimetic materials have been designed and developed to construct flexible actuators which can convert external stimuli(such as light,heat,electricity,magnetism and solvents)into mechanical deformation.Polymers have been rapidly developed and widely used in flexible driven materials because of its excellent flexibility,water absorption and biocompatibility.Carbonbased nanomaterials(such as carbon nanotubes)are also becoming important materials for the preparation of flexible actuators due to the low cost,simple preparation process,good flexibility,excellent stability,unique photoelectric properties,high electrical and thermal conductivity,etc.Typically,polydimethylsiloxane(PDMS)and carbon nanotubes(CNTs)are widely used in their respective fields.At present,CNTs/PDMS composite materials are applicable to the flexible actuation based on the photoresponse,thermal response and electrical response of carbon nanotubes.In practice,it is considered critical for flexible actuator to perform complex tasks accurately.Therefore,three key factors are indispensable for the fabrication of multi-functional soft intelligent robots with multi-response:the selection of proper materials,the method of 3D manufacturing and exactitude control system.Based on the rapid response of the PDMS to a variety of organic solvents or their vapors,PDMS and CNTs were combined to obtain CNTs/PDMS composite materials with highperformance response including higher sensitivity and faster response speed in this paper.The driving performance,corrosion resistance and stability of PDMS were enhanced remarkably with the addition of CNTs.In order to realize the controllability of the actuator,a sandwich structure actuator was proposed.Silica gel was chosen as the intermediate connection layer to enhance the fracture resistant of the multi-layer structure and improve the stability of the actuator.The actuator showed quick response under the stimulation of a variety of organic solvents or their steam(such as n-pentane,chloroform,n-hexane,cyclohexane,methylene chloride,etc.).Specifically,the response speed can reached 10 ms under the stimulation of nhexane,faster than the existing actuators and robots.Finally,the laser cutting technology was utilized to prepare the bionic actuator,which successfully simulate the mechanical movement of living beings,and realize the complex 3D controllable deformation.Due to the unique continuous and rapid bionic motion driven by organic solvent/vapor,this actuator has shown great potential in the fields of bionic,soft robot and the design of sensor electronics.