Indentation Tests Reveal Geometry-Regulated Stiffening of Nanotube Junctions

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• 作者：Sehmus Ozden ; Yang Yang ; Chandra Sekhar Tiwary ; Sanjit Bhowmick ; Syed Asif ; Evgeni S. Penev ; Boris I. Yakobson ; Pulickel M. Ajayan
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：16
• 期：1
• 页码：232-236
• 全文大小：509K
• ISSN：1530-6992

文摘

Here we report a unique method to locally determine the mechanical response of individual covalent junctions between carbon nanotubes (CNTs), in various configurations such as “X”, “Y”, and “Λ”-like. The setup is based on in situ indentation using a picoindenter integrated within a scanning electron microscope. This allows for precise mapping between junction geometry and mechanical behavior and uncovers geometry-regulated junction stiffening. Molecular dynamics simulations reveal that the dominant contribution to the nanoindentation response is due to the CNT walls stretching at the junction. Targeted synthesis of desired junction geometries can therefore provide a “structural alphabet” for construction of macroscopic CNT networks with tunable mechanical response.