Giant Stretchability and Reversibility of Tightly Wound Helical Carbon Nanotubes

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• 作者：Jianyang Wu ; Jianying He ; Gregory M. Odegard ; Shijo Nagao ; Quanshui Zheng ; Zhiliang Zhang
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：September 18, 2013
• 年：2013
• 卷：135
• 期：37
• 页码：13775-13785
• 全文大小：868K
• 年卷期：v.135,no.37(September 18, 2013)
• ISSN：1520-5126

文摘

There is a surging interest in 3D graphitic nanostructures which possess outstanding properties enabling them to be prime candidates for a new generation of nanodevices and energy-absorbing materials. Here we study the stretching instability and reversibility of tightly wound helical carbon nanotubes (HCNTs) by atomistic simulations. The intercoil van der Waals (vdW) interaction-induced flattening of HCNT walls prior to loading is constrained by the defects coordinated for the curvature formation of helices. The HCNTs exhibit extensive stretchability in the range from 400% to 1000% as a result of two distinct deformation mechanisms depending on the HCNT size. For small HCNTs tremendous deformation is achieved by domino-type partial fracture events, whereas for large HCNTs this is accomplished by stepwise buckling of coils. The formation and fracture of edge-closed graphene ribbons occur at lower temperatures, while at elevated temperatures the highly distributed fracture realizes a phenomenal stretchability. The results of cyclic stretching-reversing simulations of large HCNTs display pronounced hysteresis loops, which produce large energy dissipation via full recovery of buckling and vdW bondings. This study provides physical insights into the origins of high ductility and superior reversibility of hybrid CNT structures.