Effects of high temperature treatment of carbon nanotube arrays on graphite: increased crystallinity, anchoring and inter-tube bonding
Journal article, 2020

Thermal treatment of carbon nanotubes (CNTs) can significantly improve their mechanical, electrical and thermal properties due to reduced defects and increased crystallinity. In this work we investigate the effect of annealing at 3000 degrees C of vertically aligned CNT arrays synthesized by chemical vapor deposition (CVD) on graphite. Raman measurements show a drastically reduced amount of defects and, together with transmission electron microscope (TEM) diffraction measurements, an increased average crystallite size of around 50%, which corresponds to a 124% increase in Young's modulus. We also find a tendency for CNTs to bond to each other with van der Waals (vdW) forces, which causes individual CNTs to closely align with each other. This bonding causes a densification effect on the entire CNT array, which appears at temperatures >1000 degrees C. The densification onset temperature corresponds to the thermal decomposition of oxygen containing functional groups, which otherwise prevents close enough contact for vdW bonding. Finally, the remaining CVD catalyst on the bottom of the CNT array is evaporated during annealing, enabling direct anchoring of the CNTs to the underlying graphite substrate.

crystallinity

carbon nanotubes

annealing

heat treatment

Author

Josef Hansson

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Andreas Nylander

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Mattias Flygare

Karlstad University

Krister Svensson

Karlstad University

Lilei Ye

SHT Smart High-Tech

Torbjörn Nilsson

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Yifeng Fu

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Johan Liu

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Nanotechnology

0957-4484 (ISSN) 1361-6528 (eISSN)

Vol. 31 45 455708

Subject Categories

Inorganic Chemistry

Polymer Technologies

Materials Chemistry

Areas of Advance

Production

DOI

10.1088/1361-6528/ab9677

PubMed

32454479

More information

Latest update

10/8/2020