Effect of flake size on the mechanical properties of graphene aerogels prepared by freeze casting
Effect of flake size on the mechanical properties of graphene aerogels prepared by freeze casting
复制标题
薄片尺寸对冷冻铸造制备石墨烯气凝胶力学性能的影响
DOI：
10.1039/c7ra05557a
复制
发表时间：
2017-01-01
期刊：
影响因子：
3.9
通讯作者：
Gao, Chao
中科院分区：
文献类型：
--
作者：
Gao, Weiwei;Zhao, Nifang;Gao, Chao
气凝胶具有超低密度、超弹性、高比表面积、能量吸收能力等优点，具有广泛的应用前景，但其力学性能难以精确控制，这在很大程度上阻碍了其应用。在这里，我们通过冷冻铸造技术制备了由具有从亚微米到类似于80 μ m的不同尺寸的薄片组装的各向异性石墨烯气凝胶，使用冰作为模板将氧化石墨烯（GO）片组装成三维（3D）气凝胶。我们发现石墨烯片的尺寸对组装的石墨烯气凝胶的机械性能，特别是它们的强度、模量和压缩下的抗疲劳性具有深远的影响。较大的薄片在组装时具有更强的相互作用，这使得它们在变形期间更能抵抗相邻薄片之间的滑动。因此，具有较大片状尺寸的石墨烯气凝胶表现出更高的强度和抗疲劳性。我们的研究提供了一种新的方法来控制石墨烯气凝胶的机械性能，只需调整薄片的固有性能，例如，施胶，没有交联剂或与其他材料的共组装，如在以前的研究中。
Aerogels enable a wide range of potential applications owing to their ultralow density, superelasticity, high specific surface area, energy-absorbability and so on. However, it is usually difficult to precisely control their mechanical performance, which largely hinders their applications. Here, we prepared anisotropic graphene aerogels assembled with flakes having different sizes ranging from sub-micron to similar to 80 mu m by the freeze casting technique, using ice as a template to assembling graphene oxide (GO) sheets into 3-dimensional (3D) aerogels. We found that graphene flake size has a profound effect on the mechanical performance of the assembled graphene aerogels, particularly their strength, modulus and fatigue resistance under compression. Larger flakes had stronger interaction when assembled, which made them more resistant to slipping between adjacent flakes during deformation. As a result, the graphene aerogel with larger flake size showed both higher strength and fatigue resistance. Our research provides a new way of controlling the mechanical properties of graphene aerogel by only adjusting the intrinsic properties of the flakes, e.g., size, without crosslinking agent or co-assembly with other materials as in previous studies.