Lightweight 3D Graphene Metamaterials with Tunable Negative Thermal Expansion,Advanced Materials

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Lightweight 3D Graphene Metamaterials with Tunable Negative Thermal Expansion
Advanced Materials ( IF 27.4 ) Pub Date : 2022-11-26 , DOI: 10.1002/adma.202208562
Peng He _{1,

2} , Tao Du ₃ , Keren Zhao _{1,

2} , Jiaqi Dong _{1,

2} , Yusheng Liang _{1,

2} , Qiangqiang Zhang _{1,

2}

Affiliation

In this study, a 3D graphene metamaterial (GM) showing negative thermal expansion is prepared using a strategy of hyperbolically oriented freezing under a dual temperature gradient along orthogonal directions after the π–π stacking-derived assembly of 2D graphene sheets. As the fundamental construction element of the 3D GM, the graphene sheet displays anomalous shrinking deformation with a thermal expansion coefficient of (−6.12 ± 0.28) × 10⁻⁶ that is triggered by thermally induced out-of-plane vibrations of the CC bonds. A combination of numerical simulations and experimental investigations validates that anomalous negative thermal expansion (NTE) behavior can be effectively delivered to scalable 3D GM candidates at larger dimensions beyond the basic 2D graphene sheets at the microscale. The multiscale design and optimization of the structural characterization of the 3D GM further realize the desirable regulation of the NTE performance with the NTE coefficient ranging from negative ((−7.5± 0.65) × 10⁻⁶ K⁻¹) to near-zero values ((−0.8 ± 0.25) × 10⁻⁶ K⁻¹). This is attributed to the NTE-derived release regulation of the primary stress/strain of the microstructure, and the 3D GM exhibits high thermal stability while preserving the desirable structural robustness and fatigue resistance under thermo-mechanical coupling conditions. Therefore, this 3D GM offers promising potential for applications as protective skin, thermal actuator, smart switcher, and packing filler.

中文翻译：

具有可调负热膨胀的轻质 3D 石墨烯超材料

在这项研究中，在二维石墨烯片的π-π堆叠衍生组装之后，使用双曲线定向冷冻策略在沿正交方向的双温度梯度下制备显示负热膨胀的 3D 石墨烯超材料 (GM)。作为 3D GM 的基本构造元素，石墨烯片显示异常收缩变形，热膨胀系数为 (-6.12 ± 0.28) × 10 ^{-6 ，由 C}的热诱导面外振动触发C债券。数值模拟和实验研究的结合验证了异常负热膨胀 (NTE) 行为可以有效地传递给可扩展的 3D GM 候选者，其尺寸超过微尺度的基本 2D 石墨烯片。3D GM 的结构表征的多尺度设计和优化进一步实现了 NTE 性能的理想调节，NTE 系数范围从负（-7.5±0.65）×10 -6 K -1 ）到^接近零^值（ (−0.8 ± 0.25) × 10 ⁻⁶ K ⁻¹). 这归因于微观结构的主要应力/应变的 NTE 衍生释放调节，并且 3D GM 表现出高热稳定性，同时在热机械耦合条件下保持理想的结构稳健性和抗疲劳性。因此，这种 3D GM 为保护皮肤、热致动器、智能开关和填料填料等应用提供了广阔的前景。

更新日期：2022-11-26

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