Multiple Stimulus-responsive Materials Based Smart Actuator And Multifunctional Conductive Hydrogels

In nature,many organisms have their particular stress response properties,and human beings are inspired to imitate their responses to the changes in environmental stimuli,so that the stimuli-responsive materials come into being.For example,scientists have developed smart actuators based on polymeric polymer materials,inspiring from the opening and closing of plant seeds when they respond to external environmental stimuli,and have successfully designed smart actuators with multiple structures and multiple stimuli responsiveness device.Stimulus-responsive actuators that the materials respond to external environmental stimuli such as humidity,light,electricity,temperature,magnetic fields,p H,ionic strength and so on,which respond to changes in size or shape.However,at present,most actuators have only a single stimuli response,and have a short displacement distance,a slow response time,only a unidirectional bending and other problems exist.Therefore,it is necessary to design and develop actuators with multiple stimuli-responsiveness,and precisely control their movement under different environmental stimuli responsivene ss,which will greatly expand the potential application fields of stimuli-responsive actuators..In addition,if this polymer material based on stimuli-responsiveness is applied to the preparation of hydrogels,there will be a wide range of potential applications in areas such as smart wear,biomedical care,and the like.Therefore,in this paper,we have carried out the study of actuators based on multiple stimulus-responsive macromolecule materials and the study of repairable,pasteable and wearable hybrid conductive hydrogels.Its main research work includes the following two aspects:1.Using a natural moisture-sensitive material in combination with a conductive polymer,a multiple stimuli responsiveness smart actuator was prepared by constructed the polypyrrole nanoparticles with agar composite material.First,the smart actuator not only exhibit multiple stimuli responsiveness,such as humidity,light,temperature,ammonia,and hydrogen chloride gas stimuli,but also can return to their original shape after removing these stimuli,and can also under a single stimuli response(such as humidity)control circuit connection and disconnection.Second,the smart actuator can control the direction of its bending through external stimuli,and through the stimulation of humidity and light,the smart actuator can bend away from the two stimuli.By controlling the application of these two stimuli on smart actuators,smart actuators can produce a phenomenon that continuously changes the bending angle.Third,based on these two stimuli,we have also found that a one-cycle conversion of the shape of the actuator from sheet to hemi-tubular.At the same time,this kind of multi-stimulus-responsive synergistic function is applied to the device field,and a walking device can be prepared which have functions of loading,transporting,and releasing of cargo.In the future,we believe that this multi-stimulus responsive multi-functional smart actuator will have significant development prospects in the field,such as photoelectric sensing,intelligent robots and so on.2.By simple mixing the natural polymer hydrogels(agar)with new functional materials(graphenes)of high electrical conductivity,a adhered,wearable,mixed conductive hydrogel can be prepared at large-scale,which can be realized self-healing under near-infrared laser irradiation.This hybrid conductive hydrogel exhibits not only the unique water-swelling properties of the hydrogel,but also enables controlled self-healing behavior under light irradiation,and this process enables remote control.In addition,this conductive hybrid hydrogel has adhesive properties and can be directly in contact with human skin,such as the fingers,back of the hand,wrists,and elbows.Moreover,the mixed conductive hydrogel can not only be stuck on the skin of the human body,but also can detect the activity of the human body.For example,by changing the curvature of the finger joints,we can test the change in the resistance value of the mixed conductive hydrogel,and this change is used to reflect the activity of the human body.In addition,since the graphene in the hybrid hydrogel has high conductivity,it can convert the resistance value change into an electrical signal,and it can have a wide range of application prospects in the fields,such as electronic skin,biomedical care,sensing and so on.