Microwave Makes Carbon Nanotubes Less Defective

Abstract

An ultrafast microwave annealing process has been developed to reduce the defect density in vertically aligned carbon nanotubes (CNTs). Raman and thermogravimetric analyses have shown a distinct defect reduction in the CNTs annealed in microwave for 3 min. Fibers spun from the as-annealed CNTs, in comparison with those from the pristine CNTs, show increases of approximately 35% and approximately 65%, respectively, in tensile strength ( approximately 0.8 GPa) and modulus (approximately 90 GPa) during tensile testing; an approximately 20% improvement in electrical conductivity (approximately 80000 S m(-1)) was also reported. The mechanism of the microwave response of CNTs was discussed.

New strategies for the chemical characterization of multi-walled carbon nanotubes and their derivatives

“…[38] The characterization of multi-wall carbon nanotubes by Raman spectroscopy has been mainly focused on the comparison between the G band, which originates from the carbon-carbon bonds in-plane tangential and longitudinal stretching, and the D band, which is attributed to the presence of amorphous carbon or sp^3-defects in the graphene structure. The ratio between the areas of these two bands (A D /A G ) has been used to quantify the degree of purification [40][41][42] or functionalization [43] of multi-wall carbon nanotubes. In some cases, however, it led to contradictory results.…”

Use of Carbon nanotubes in potential electronics packaging applications

“…In electronics packaging we normally utilize CNT bundles a few tens to a few hundred micrometers long, making this requirement very difficult to meet. Improvements of the structural quality can be made by optimization of the growth process [71,72] and post growth annealing at high temperature [73] or by microwave [74].…”

Microwave heating of carbon-based solid materials

“…Much more detailed analyses were made by Lin et al [17] in 2010. After 3 min of microwave irradiation, the thermal stability, mechanical property, and electrical property of CNTs were improved and the D/G ratio of CNTs was decreased.…”