Year-end Sale % OFF 
Abstract
We have investigated the scalability of our post-synthesis graphitization process for single-walled carbon nanotubes (SWCNTs), which applies heat and current to SWCNTs to improve the thermal and electrical conductivities. This investigation was performed by examining the relationship between the processing conditions and the amount of treated SWCNTs. Characterization of all cases of treated SWCNTs showed the same level of improvement of ~3 times to both the thermal and electrical conductivities and that the SWCNTs remained SWCNTs, i.e., no change in diameter or wall number. These results provided evidence that the ability to improve the crystallinity of the SWCNTs was independent of the treatment amount. Further, our results showed that an increase in SWCNT amount required increased applied current density or increased in applied temperature to achieve optimum property improvement. Finally, we found a trade-off between the current density and temperature indicating that either a high current or high temperature was required to achieve the optimum process conditions. These results demonstrated that our heat and current SWCNT treatment was fundamentally scalable and applied towards larger scale (i.e., gram-level or more) amounts of SWCNT.
Highlights
Defects in the crystalline structure of carbon nanotubes (CNTs) represent the bottleneck for their applications
A vacuum chamber was equipped with a high-frequency induction heating system and isotropic carbon electrodes that treated the aligned Single-walled carbon nanotubes (SWCNTs) sheets of 10 × 10 mm2 in size (~3.0 mg each) which was connected to high DC power supply (Fig. 2) [19]
Insufficient contact between the electrodes and the aligned SWCNT sheet resulted in electrical discharge; if the electrodes and SWCNT sheet were first placed in contact and heated, thermal expansion of the electrodes would damage both the SWCNT sheet and electrodes
Summary
Defects in the crystalline structure of carbon nanotubes (CNTs) represent the bottleneck for their applications. Single-walled carbon nanotubes (SWCNTs) can, in principle, possess a perfectly defined structure because the chemical structure can be completely determined by its chirality. The presence of crystalline defects significantly diminishes the measured properties [1]. A defect-free SWCNT is predicted to possess a tensile strength of ~400 GPa, yet tensile strengths of only ~3 GPa have been experimentally observed from SWCNT fibers [2,3,4]. The thermal conductivity for SWCNTs is estimated to be ~6600 W m−1 K−1 at room temperature, but the observed thermal conductivity of a SWCNT bundle (diameter, 10 nm) is only ~150 W m−1 K−1 [5, 6].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
