Thermally activated interlayer bonding in multiwalled carbon nanotubes

Recent experimental and theoretical results show that interlayer bonds in multiwalled carbon nanotubes (MWCNTs) play a pivotal role in improving their mechanical and electronic properties desirable for device applications. However, generation of interlayer bonds while maintaining tube structural integrity remains a key challenge. Here we demonstrate by molecular dynamics simulations that high-temperature thermal treatment can controllably activate interlayer bonding in MWCNTs and few-layer graphene systems, which leads to a significant improvement in their mechanical properties such as load carrying capacity and high-temperature tensile ductility. Moreover, first-principles calculations show that interlayer bonding opens up energy gaps in metallic MWCNTs, providing a way to produce all-semiconducting MWCNTs. These results offer new insights into the behavior of MWCNTs and raise prospects of effective thermal engineering of their structural, mechanical, and electronic properties.