Strong, Ultralight Nanofoams with Extreme Recovery and Dissipation by Manipulation of Internal Adhesive Contacts
Strong, Ultralight Nanofoams with Extreme Recovery and Dissipation by Manipulation of Internal Adhesive Contacts
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DOI：
10.1021/acsnano.0c02422
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发表时间：
2020-07-28
期刊：
影响因子：
17.1
通讯作者：
Hart, A. John
中科院分区：
文献类型：
--
作者：
Park, Sei Jin;Shin, Jungho;Hart, A. John
三维纳米制造技术的进步使得轻质固体的开发成为可能，例如空心纳米晶格，尽管生产量较低，但其比刚度和强度却创下了记录。在这些固体的结构元件的长度尺度上（通常为数十纳米或更小），弹性变形所需的力可以与粘附力相当，从而可以根据这些力的相对平衡来定制整体机械性能。在此，我们通过超轻陶瓷涂层碳纳米管（CNT）结构的力学研究这种相互作用。我们表明，陶瓷-碳纳米管泡沫在密度归一化强度方面优于其他结构的纳米材料，并且当结构设计为最大限度地减少碳纳米管之间的内部粘合相互作用时，超过致密化的压缩后超过 97% 的应变得到恢复。通过实验和建模，我们研究了恢复和耗散对涂层厚度的依赖性，证明内部粘合剂接触阻碍恢复，并确定超轻材料具有最大恢复的设计指南。陶瓷碳纳米管泡沫的高恢复性和耗散性的结合可能有助于结构阻尼和减震，并且一般原理可以广泛应用于结构纳米泡沫和随机纳米泡沫。
Advances in three-dimensional nanofabrication techniques have enabled the development of lightweight solids, such as hollow nanolattices, having record values of specific stiffness and strength, albeit at low production throughput. At the length scales of the structural elements of these solids-which are often tens of nanometers or smaller-forces required for elastic deformation can be comparable to adhesive forces, rendering the possibility to tailor bulk mechanical properties based on the relative balance of these forces. Herein, we study this interplay via the mechanics of ultralight ceramic-coated carbon nanotube (CNT) structures. We show that ceramic-CNT foams surpass other architected nanomaterials in density-normalized strength and that, when the structures are designed to minimize internal adhesive interactions between CNTs, more than 97% of the strain after compression beyond densification is recovered. Via experiments and modeling, we study the dependence of the recovery and dissipation on the coating thickness, demonstrate that internal adhesive contacts impede recovery, and identify design guidelines for ultralight materials to have maximum recovery. The combination of high recovery and dissipation in ceramic-CNT foams may be useful in structural damping and shock absorption, and the general principles could be broadly applied to both architected and stochastic nanofoams.