Transformation Behaviors And Mechanism Of Multistimulus Responsive Actuating Materials

Smart soft materials are a class of material which are capable of producing responsive deformation through external stimulation such as temperature,humidity,pH value,electrolyte solution,electric field,magnetic field and light.Generally,these materials have the advantages such as low price,light weight,large deformation and fast response,which result in their widespread applications in soft robots,intelligent sensors,biomimetic actuators,artificial muscles,etc.As far as the present researches are concerned,there are still two issues to work out.One is that only a few soft materials can respond to more than three stimuli,which means it is still challenging to develop smart actuators possessing multi-stimuli response ability since multi-stimuli response can be used and even combined to enable soft actuator to realize shape changes in different environments or integrated functions.The other is that the present preparation technologies of actuation materials cannot design the shapes and patterns easily and controllably.In order to solve these two problems,the main contents and results about this dissertation are summarized as follows:?1?Multi-stimuli responsive soft actuator with PNIPAM brushes modified Fe3O4/PDMS composite.A multi-stimuli soft actuator was fabricated by grafting PNIPAM brushes on the surface of Fe₃O₄ nanoparticles doped PDMS composite?Fe₃O₄/PDMS?.The obtained PNIPAM-Fe3O4/PDMS actuator demonstrated fast,reversible and sensitive deformation and actuation behaviors under various environmental stimuli including near infrared light?NIR?,heat,magnetism and various organic vapors.Based on the reversible deformation of PNIPAM-Fe₃O₄/PDMS using NIR irradiation,the demonstrations show the potential applications in smart devices such as sundial-like device and intelligent curtain.In addition,PNIPAM-Fe3O4/PDMS actuator can be used as cargo transportation microsystem due to its combined response to NIR light and magnetic stimulation.The results showed that PNIPAM-Fe₃O₄/PDMS composite may have great potential applications in smart actuators.?2?Digital coding of shape deformation in a gradient crosslinking hydrogel prepared by3D printing.The hydrogel precursor ink was prepared with the PEGDA 600 and the additives including thinners,crosslinkers,photosensitizers,photoresists and dyes.The obtained hydrogel precursor ink was printed as gradient crosslinking hydrogel using 3D printing.The printed hydrogels would occur shape deformation while immersing into water owing to swelling mismatch in different local areas of hydrogels.Importantly,the single materials without apparent designed structures can readily to construct tailored and complex shape,including two dimensional to three dimensional and three dimensional to three dimensional deformations.In addition,the gradient crosslinking hydrogel was designed and printed controllably as biomimose leaves and the humidity alarm.The results showed that the integration of advanced grayscale 3D printing technique and various hydrogels uncovers a facile strategy to broad opportunities for sensors,soft robots,actuators and many other intelligent devices.?3?Multi-stimuli responsive soft actuator based on toner/polyethylene?PE?composite.We present a simple method of office laser-printing to fabricate a polyethylene-based soft actuator.It has controllable shape and pattern design and can realize multiple stimuli response.The obtained toner/PE actuator demonstrated fast,reversible and sensitive deformation and actuation behaviors under various environmental stimuli including near infrared light?NIR?,heat,magnetism and various organic vapors.Due to the easy,fast and controllable characteristics,the office laser-printing technology can be applied widely in preparing smart soft materials.