Near-Infrared Light Stimuli-Responsive Layered Structure Actuators Based On Graphene Oxide

Smart actuators offer a well controllable and reversible shape changes in response to environment stimuli and hold great promise for developing the next-generation smart products.Graphene and its derivatives are attractive materials for fabricating high-performance actuator,mainly due to their atom-thick two-dimensional structures,low weight densities,large specific surface areas,high mechanical strengths and electrical conductivities.Furthermore,graphene oxide(GO),one of the most important graphene derivatives,has abundant oxygenated groups and excellent film-forming properties which made GO film be able to change its lamellar space via adsorbing/desorbing water molecules.Meanwhile,GO has eximious thermal conductivity and infrared(IR)response,making it be able to composited the IR-driven actuator.Besides,GO has with two-dimensional lamellar structure,can be used as the base material of actuator.Here,we introduce thermo-sensitive macromolecular,Poly(N-isopropylacrylamide)(PNIPAM),to modified the GO film.The temperature dependent porperty allows PNIPAM to swell or collapse in the presence of water with changes in temperature and driven the GO film bending motion at the Near-Infrared Light(NIR).Thus,we prepared two kinds of NIR actuators based on the GO film.1.Here,we obtained PNIPAM-grafted GO nanocomposites(GOgP)through an in-situ polymerization using Ce(IV)/HNO3 redox system as initiator.During the vacuum-assisted filtration process,PNIPAM-grafted GO sheets assembled into hybrid films with layered structure.The mechanical properties of different PNIPAM content of hybrid films were investigated in this study.Meanwhile,the bilayer actuator was assembled by the GOgP layer and GO layer via the two-steps vacuum filtration method and the NIR-driven process of the bilayer actuator has been studied.2.Because the PNIPAM has strong hydrogen bond interaction with GO,we could attach PNIPAM to the GO sheets to form the nanocomposites named GmP.We describe the fabrication of a novel NIR light-driven bilayer actuator,via a facile two-step vacuum filtration method in this study.Our bilayer actuator consists a layer of GO,and a layer of GmP hybrid.The bilayer film exists excellent reversible bending/unbending behaviors upon the periodic NIR light.Remarkably,our actuator shows templated bending orientation once exposed to NIR light,and exhibits shape memory effect.we further designed and fabricated an interesting smart "forklift truck".3.The GO film was fabricated by vacuum filtration method or blade coating method.And reduced graphene oxide(RGO)/GO was prepared by HI acide fumigation method.It has obvious phenomena of bending by water vapor,and the influence of different sizes of RGO/GO on the phenomenon of bending was disscued.We find that the RGO/GO exhibits shape memory effect when the films made by the blade coating method.