Study On The Structured Design And Performance Of 3D Printed Graphene Metamaterial

Graphene has excellent mechanical,electrical and thermal properties,which makes it have broad application prospects in the field of new metamaterials.Precise multi-scale structure tailoring and controllable geometric design of 3D printed graphene aerogels,based on the principle of "additive manufacturing",makes its excellent intrinsic properties have multi-functional applications on macroscale.At the same time,controllable modulation and modification optimization of performance can be achieved through multi-scale structured design.It is of great significance to promote the application of graphene in multiple fields such as protective materials,electronic devices,intelligent sensing functional materials and so on.In this paper,we designed and printed three-dimensional graphene metamaterial structures(concave quadrilateral,concave hexagon,chiral structure,etc)with tunable negative Poisson's ratio by the research on the key method of 3D printed graphene metamaterials based on direct ink writing,and revealed the influence of the structure's multi-scale characteristics on the deformation behavior of auxetic materials and the control mechanism of mechanical properties combining with finite element modeling and analysis.In this paper,we also explored the mechanical behavior and electromechanical response characteristics of three-dimensional graphene-based materials encapsulated by polymer materials.The specific research content is as follows:Firstly,the multi-scale controllable construction of 3D printed graphene metamaterial with tunable negative Poisson's ratio was realized through the 3D printing method of graphene aerogel using graphene oxide precursor solution as the raw material.The experimental results showed that when the ink output rate is maintained at 80~90 ?L/min,the 3D printed graphene metamaterial has good molding accuracy.When the concentration of the graphene oxide solution precursor is 8~10mg/mL,the 3D printed graphene metamaterial has large compressive strain and obvious negative Poisson's ratio deformation characteristics.Secondly,the adjustability of the negative exponential mechanical behavior of the material can be studied combining with theoretical modeling analysis and mechanical performance experiments through the design and analysis of multi-scale structured parameters.The experimental results showed that the 3D printed graphene metamaterials have excellent elastic properties(maximum compressive strain can reach 90%),and the Poisson's ratios of concave quadrilateral and chiral structure can reach-0.22 and-0.34.Finally,the 3D printed graphene metamaterial can be flexibly encapsulated by polydimethylsiloxane.The influence law on the mechanical and electromechanical response characteristics of the material can be studied through the design of the geometrical structure parameters of the material.The experimental results show that the material has excellent compressive properties and good resilience even after large compressive strain(90%).In addition,the compound system can achieve a larger mechanical negative index(the Poisson's ratios of concave quadrilateral and chiral structure can reach-0.43 and-0.47,respectively).