Boron-Filled Hybrid Carbon Nanotubes.

Joseph Lefebvre,Rajen B. Patel,Frank Owens,Alokik Kanwal,Zafar Iqbal,Tsengming Chou,David J. Apigo

doi:10.1038/srep30495

Abstract

A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs.

Highlights

Carbon is able to form a large number of unique nanostructures, such as closed hollow carbon cages otherwise known as fullerenes[1,2,3,4,5]
The weaknesses of CNTs mentioned previously are mitigated by growing multiwalled CNTs (MWCNTs) around boron nanowires, with both materials grown in one step, to create boron filled hybrid carbon nanotubes (BHCNTs)[31]
The results show that the unaltered double-walled carbon nanotubes (DWCNT) is the most stable of the structures having a binding energy (BE) of 628.6020 AU

Summary

Introduction

Carbon is able to form a large number of unique nanostructures, such as closed hollow carbon cages otherwise known as fullerenes[1,2,3,4,5]. Multiwalled CNTs (MWCNTs) with few available defect bonding sites have little wall to wall adhesion (causing superlubricity, which is useful for some applications)[29], leading to the outer wall bearing the vast majority of any mechanical loading[6] To mitigate these issues, the general approach has been to add functional groups or use radiation to induce defects after the production of the CNTs to bond adjacent walls of the nanotubes together[30]. MWCNTs grown around boron nanowires possess a ‘corrugated’ structure, which may allow loading to transfer more effectively from the outer wall of a MWCNT This uneven shape seems morphologically analogous to a 1-D form of crumpled graphene[36]. The emergence of these unexpected properties differentiate BHCNTs from traditional filled carbon nanotubes, making them a hybrid form of nanotubes

Methods

Results

Conclusion