Molecular dynamics simulation of single wall carbon nanotubes polymerization under compression

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Single wall carbon nanotubes (SWCNTs) naturally aggregate into bundles.
• Cross-polymerization of SWCNTs offers potential for creating super-hard materials with novel properties and applications.
• Previous theories attributed structural changes during compression to geometric modifications of the radial section.

Purpose of the Study:

• To investigate the polymerization of small diameter armchair single wall carbon nanotubes (SWCNTs) under compression using molecular dynamics simulations.
• To explore the influence of compression type, temperature, and rate on SWCNT polymerization.
• To identify emergent structures and compare simulation results with existing theoretical predictions.

Main Methods:

• Molecular dynamics simulations were employed to model the compression of small diameter armchair SWCNTs.
• Simulations included both hydrostatic and piston-type compression scenarios.
• Variations in temperature and compression rates were systematically applied.

Main Results:

• Small diameter SWCNTs (around 5 Å) demonstrate polymerization even at room temperature.
• Large diameter SWCNTs (e.g., (10,10) tubes) show limited propensity for polymerization.
• Spontaneous formation of scroll-like structures and tubulane motifs were observed, consistent with prior theoretical predictions.

Conclusions:

• The polymerization of SWCNTs is highly dependent on their diameter, with smaller tubes being more amenable to this process.
• Simulations successfully reproduced predicted tubulane structures and revealed novel scroll-like formations.
• This study provides critical insights into the formation of condensed SWCNT structures for advanced material development.