Coaxial carbon@boron nitride nanotube arrays with enhanced thermal stability and compressive mechanical properties

Abstract

Vertically aligned carbon nanotube (CNT) arrays have aroused considerable interest because of their remarkable mechanical properties. However, the mechanical behaviour of as-synthesized CNT arrays could vary drastically at a macro-scale depending on their morphologies, dimensions and array density, which are determined by the synthesis method. Here, we demonstrate a coaxial carbon@boron nitride nanotube (C@BNNT) array with enhanced compressive strength and shape recoverability. CNT arrays are grown using a commercially available thermal chemical vapor deposition (TCVD) technique and an outer BNNT with a wall thickness up to 1.37 nm is introduced by a post-growth TCVD treatment. Importantly, compared to the as-grown CNT arrays which deform almost plastically upon compression, the coaxial C@BNNT arrays exhibit an impressive ∼4-fold increase in compressive strength with nearly full recovery after the first compression cycle at a 50% strain (76% recovery maintained after 10 cycles), as well as a significantly high and persistent energy dissipation ratio (∼60% at a 50% strain after 100 cycles), attributed to the synergistic effect between the CNT and outer BNNT. Additionally, the as-prepared C@BNNT arrays show an improved structural stability in air at elevated temperatures, attributing to the outstanding thermal stability of the outer BNNT. This work provides new insights into tailoring the mechanical and thermal behaviours of arbitrary CNT arrays which enables a broader range of applications.

Growth of Carbon Nanotubes inside Boron Nitride Nanotubes by Coalescence of Fullerenes: Toward the World's Smallest Coaxial Cable

“…The polymerization and coalescence of guest C 60 molecules into a CNT inside the host BNNT offer an exciting opportunity to form a conducting nanowire inside an insulating BNNT. Previous attempts to fabricate CNT@BNNT have been made by other routes, such as the coating of CNT with boron nitride . However, the formation of CNTs within preformed BNNTs would be more desirable because the structure of the outer insulating nanotube is well‐defined and easier to control with uniform coverage of BN.…”

Synthesis, characterisation and applications of core–shell carbon–hexagonal boron nitride nanotubes

“…H 3 BO 3 or CO(NH 2 ) 2 ). 21,22,29,[31][32][33][34][35]49 Such aqueous precursors are deposited onto the CNT surface, and this precoat is subsequently reacted in the furnace to form h-BN. Controlling the extent of the precursor coverage, for example by longer duration of inltration, 33 affects the thickness of the nal h-BN coating, thereby determining the effective h-BN growth rate.…”

“…20 h-BN sheaths may also enhance the mechanical robustness and provide additional thermal conduction pathways along the CNT axis. [21][22][23] The emergent properties of CNT@BN heteronanotubes lend to their proposed applications as reinforcement llers in high temperature ceramic/metal matrix composites, energy dissipating devices, nanocables, high density interconnects, thermal interface materials, thermal management polymer composites and eld emitters.…”

Finite element investigation of the elastic modulus of concentric boron nitride and carbon multi-walled nanotubes

“…In addition to pure CNTs and BNNTs, physical properties of the coaxial BNNT/CNT have also been considered. Thermal stability and compressive mechanical properties of coaxial CNT/BNNT arrays were investigated by Jiang et al [40]. Besides, the heat transfer in the coaxial CNT/BNNT arrays was also investigated by Jing et al [41] by molecular dynamics (MD) simulations.…”