Customizable fabrication for auxetic graphene assembled macrofilms with high conductivity and flexibility

Abstract

Auxetic materials with negative Poisson's ratios unusually exhibit intuitive mechanical behaviors, such as cross-section expansion instead of contraction during tension. Such behaviors are interesting because they may enhance unusual mechanical properties. However, controllable preparation of materials with negative Poisson's ratio is still a major challenge.In this study, we report the synthesis of a flexible auxetic graphene assembled macrofilm (GAMF) from graphene oxide nanosheets by a thermal annealing and press assistant method.The obtained materials exhibit good flexibility and significantly wide tunable negative Poisson s ratios ranging from -0.11 to -0.53. We also develop a reconstruction model for characterization the uniaxial tension of GAMF based on X-ray tomographic images. The tensile simulation result predicts the function relationship between Poisson's ratio and critical thickness of pore channels, which is in good agreement with the experimental data. As a result, an effective tunable way is proposed for customizable fabrication of GAMF with tunable negative Poisson's ratios, and the GAMF materials with good flexibility, high electrical conductivity and superior auxetic behavior looks promising for future development of wearable electronics.

Low profile and miniaturized dual‐band antenna based on graphene assembled film for wearable applications

“…The surface resistivity is 36 mΩ/sq, Therefore, the conductivity of 25 μm GAF used in this article can reach 1.11 Â 10 6 S/m which is far beyond textile conductive materials. 30,31 Furthermore, the GAF has tremendous mechanical properties 32 and passed the 180 large-angle cyclic bending pressure test. 8,11,33 The results are shown in Table . 2.…”

Compressed Graphene Assembled Film with Tunable Electrical Conductivity

“…Wan et al succeeded in the scalable fabrication of graphene sheets with high strength of 1.55 GPa and improved electrical conductivity by freezing stretch-induced alignment for graphene layers [ 26 ]. Different reduction methods for graphene oxide (GO) to tune the negative Poisson’s ratio for auxetic reduced GO film were also reported by researchers [ 27 , 28 ]. By growing the graphene on metal surfaces, Deck et al reported an excellent exciton-dominated optical response [ 29 ].…”

Complex Analysis of an Auxetic Structure under Compressive Loads

“…Depending on how this relative deformation occurs, we can speak of natural materials ν ∈ (0; 0.5) or materials with auxetic character in which Poisson's ratio has negative values [10,11]. Owing to their counterintuitive deformation characteristics, the auxetic materials [12] present numerous extraordinary mechanical properties like energy absorption [13], plane-strain fracture toughness [14], fracture resistance [15], indentation resistance [16], impact resistance [17], hardness, shear resistance [18], blast resistance and other excellent properties, and potential to form synclastic curvatures under out-of-plane bending [19][20][21]. The mechanical performance of the cellular structures depends on the loading direction, and these cellular structures are usually anisotropic [22].…”