Self-assembly Of Functional Graphene-based Actuator And Its Vapor/liquid-driven Motions

Smart materials with efficient energy conversion have shown potential applications in some hot issues.Facile fabrication and fast response remain challenging in exploring new kinds of actuators.In this paper,a graphene oxide/cellulose acetate?GO/CA?composite driver and a globular reduced graphene?RGO?mini-motor have been self-assembly fabricated to response to organic vapor or liquid with graphene oxide?GO?as the precursor.Their vapor or liquid driven-motion has been studied.The main contents are summarized as follows:Acetone vapor-responsive bilayer actuator was fabricated through layer-by-layer assembly of a GO film on a flexible commercial CA polymer film.The bending angle of GO/CA actuator in acetone vapor can be easily regulated by varying its length and the thickness of GO film.Typically,the GO/CA actuator with a strip length of 30 mm and a GO film thickness of 29?m exhibits a high bending angle of 720^o within 19 s driven by acetone vapor,and can recover its shape back within 38 s in air.A bending mechanism of GO/CA bilayer actuator is proposed based on the swelling effect of one side of CA polymer in alcohol vapors,while its other side keeps constant because of organic vapors can be completely blocked by GO film,thus developing asymmetric bending.The designed actuator that response to several organic vapors with different bending is related to the solubility parameter values of the polymer and organic solvent.The new driven system is used in example applications for designing various devices to demonstrate the dynamic process.Self-assembly of graphene mini-motor has been constructed by the combination of shear-driven aggregation and capillary force induced drying followed by the high temperature reduction using graphene oxide suspension as the precursor and aniline as the crosslinking agent.The RGO mini-motor shows ethanol-driven motion and oil adsorption performance because of its small size?about 2⁵ mm in diameter?,low density(about 0.2⁰.7 g cm^-3),hollow structure and hydrophobic oleophilicity.It is found that the fastest speed of ethanol-driven rotation can reach 3 r s^-1,and the saturated adsorption capacity is 794.9 mg g^-1.