Preparation And Application Of Electrospun PNIPAM Fiber-based Composite Hydrogel Actuator

As the fourth generation of materials,intelligent materials are new functional materials that can respond to external stimuli（such as light,heat,magnetism,p H,etc.）.As an important component of intelligent materials,stimulation-responsive hydrogels have been widely used in the field of actuators owe to their excellent biocompatibility,soft and wet properties and high water content.However,the contradiction between the actuation speed and the strength of the hydrogel actuator,as well as the problems of single deformation and coordination of each performance greatly limit its further application.In addition,the hydrogel actuator at present can only produce its own complex deformation,and the synergistic combination with the spatial displacement in a large range cannot be realized.In order to solve the above problems,in this paper,the thermosensitive material poly-isopropylacrylamide and 4-benzoylphenyl acrylate copolymer（P（NIPAM-ABP））were used as the substrate,and the electrospinning technology was combined to prepare hydrogel actuator with excellent comprehensive performance,and its application was explored.The specific contents of this paper are as follows:1.Combining the excellent temperature sensitivity of P（NIPAM-ABP）and the high photothermal conversion efficiency of polypyrrole（PPy）,an ultra-thin hydrogel actuator with high strength,photothermal response and fast response was prepared.The structure and properties of PPy-P（NIPAM-ABP）hydrogel were characterized by SEM,UV-Vis,contact angle tester and mechanical testing machine.The results showed that PPy-P（NIPAM-ABP）hydrogel was composed of P（NIPAM-ABP）nanofibers with highly oriented arrangement,and its thickness was only 15±3μm,but its tensile strength was up to 5.12±0.35 MPa.In addition,the constructed PPy-P（NIPAM-ABP）hydrogel also has excellent photothermal response,which can be controlled by remote near-infrared light.2.The PEGDA-CNF/PPy-P（NIPAM-ABP）hydrogel actuator with dual response,high strength,fast response speed and programmable complex deformation was prepared by combining the PPy-P（NIPAM-ABP）hydrogel and polyethylene glycol diacrylate-cellulose layers.Then,the structure and performance of PEGDA-CNF/PPy-P（NIPAM-ABP）hydrogel actuator were characterized by SEM and mechanics testing.Through the system test,the actuation performance of PEGDA-CNF/PPy-P（NIPAM-ABP）hydrogel actuator was studied,including response speed,recovery speed,cycling performance,programmable complex deformation and self-extracting weight,etc.,and the deformation process of PEGDA-CNF/PPy-P（NIPAM-ABP）hydrogel actuator was simulated by finite element simulation.The results show that the PEGDA-CNF/PPy-P（NIPAM-ABP）hydrogel actuator can reach the mechanical strength of 3.42±0.46 MPa,the bending speed of 1286 ^o/s,and the performance can still maintain more than 95%after 100bending cycles.Moreover,the PEGDA-CNF/PPy-P（NIPAM-ABP）hydrogel actuator has complex three-dimensional deformation and strong grasping force,and can achieve effective coordination among all performance.3.Based on the theoretical exploration of P（NIPAM-ABP）based composite hydrogel actuator,P（NIPAM-ABP）and Fe₃O₄/PAN were combined by electrostatic spinning.A Fe₃O₄/PAN-P（NIPAM-ABP）composite hydrogel actuator combining magnetic response directional navigation and photothermal self-deformation was prepared.The addition of Fe₃O₄nanoparticles can not only provide magnetic response navigation for the long-distance transportation of Fe₃O₄/PAN-P（NIPAM-ABP）composite hydrogel actuator,but also make the actuator rapidly deformation in photothermal response.In addition,the introduction of electrospinning can also make it have high strength（4.59 MPa）,fast response speed（178°/s）and programmable complex photothermal deformation.More importantly,the hydrogel actuator can achieve more complex and higher-level programmable actions than before through the synergistic effect of remote deformation and remote transmission,which can be used to design a variety of new bionic soft robots.