Preparation And Photoresponse Research Of Flexible Graphene-based Bilayer Films

Due to its non-contact and precise remote control,optical stimulation has attracted more and more attention to micro-robots in new microbiology robots or biological micro-engines.The excellent photothermal conversion properties of graphene make it extremely useful in the application of photoresponsive stimulus materials.In this paper,graphene(GNP),redox graphene(RGO)and polydimethylsiloxane(PDMS)were used as the basic materials,and further combined with other polymer materials(thermal expansion microspheres(TEM)and electrospinning silk protein film(SF))to prepare two bilayer composite films with different near-infrared(NIR)response deformation patterns,GNPs-PDMS/PDMS double-layer composite film and RGO-TEM-SF-PDMS/PDMS Double layer composite film.According to their different deformation patterns,their application examples in different fields are designed.The main work of this article focuses on the following three parts:(1)Preparation and Deformation of GNPs-PDMS/PDMS Bilayer MembraneIn this paper,a GNPs-PDMS/PDMS double-layer composite membrane was fabricated by spin-coating a layer of PDMS onto a thin layer of GNPs/PDMS.Using the photothermal conversion property of graphene,light energy is converted into heat upon irradiation of near-infrared light and transmitted to the double-layered film.Due to the difference in the coefficient of thermal expansion(CET)between the GNPs/PDMS layer and the PDMS layer,the double-layer composite film is bent to the side where the coefficient of thermal expansion is small.It has been found that when the NIR is irradiated to the side of the GNPs/PDMS layer,the two-layer actuator exhibits two-stage bending deformation.This article also studied the factors that affect the deformation of double-layer composite film.(2)Preparation and Deformation Rule of RGO-TEM-SF-PDMS/PDMS Bilayer Composite MembraneIn this paper,RGO-TEM-SF-PDMS/PDMS double-layer composite membrane was fabricated by a simple knife coating method.Also using the excellent photothermal conversion property of graphene,when the near-infrared light is irradiated,the light energy is converted into heat and transferred to the double layer film.The thermal expansion microspheres will undergo rapid expansion at a certain temperature,and the volume will increase to tens of times.This results in a larger difference in the thermal expansion coefficient between the RGO/TEM/SF/PDMS layer and the PDMS layer,resulting in greater bending.Deformation.And this bending deformation state can be well maintained.Due to the addition of electrospinning protein,the mechanical performance of the actuator has been significantly improved.This article also studied the factors affecting the deformation effect of the double-layer composite film.(3)Application of GNPs-PDMS/PDMS double layer composite film and RGO-TEM-SF-PDMS/PDMS double layer composite filmAccording to the characteristics of fast and reversible deformation of GNPs-PDMS/PDMS double-layer composite film,a robot-like gripper is proposed.The double-layer actuator can be applied in biomedical fields such as drug delivery and implantation.Medical robots,etc.We made RGO-TEM-SF-PDMS/PDMS a living hinge,which can transform the planar 2D structure into a three-dimensional structure,and can achieve different degrees of deflection deformation by adjusting the length of the hinge,thus achieving a more complex three-dimensional structure.This is expected to find applications in areas where space can be expanded and autonomous installations.