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Continuous Synthesis of Double-Walled Carbon Nanotubes with Water-Assisted Floating Catalyst Chemical Vapor Deposition
摘要： Double-walled carbon nanotubes (DWCNTs) were synthesized and continuously collected using a water-assisted ?oating catalyst chemical vapor deposition (FCCVD) method. Di?ering from the conventional water-assisted synthesis in which water vapor is one part of the carrier gas mixture, we included de-ionized water in the catalyst system, which achieved a more uniform and controlled distribution for e?cient DWCNT production. Using a water-assisted FCCVD process with optimized conditions, a transition from multi- to double-walled CNTs was observed with a decrease in diameters from 19–23 nm to 10–15 nm in tandem with an elevated Raman IG/ID ratio up to 10.23, and corroborated from the decomposition peak shifts in thermogravimetric data. To characterize the mechanical and electrical improvements, the FCCVD-CNT/bismaleimide (BMI) composites with di?erent water concentrations were manufactured, revealing high electrical conductivity of 1720 S/cm along the bundle alignment (collection) direction, and the nano-indentation tests showed an axial reduced modulus at 65 GPa. A consistent value of the anisotropic ratio at ~3 was observed comparing the longitudinal and transverse properties. The continuous capability of the presented method while maintaining high quality is expected to result in an improved DWCNT mass production process and potentially enhance the structural and electrical applications of CNT nanocomposites.
关键词： water-assisted FCCVD,anisotropic ratio,double-walled carbon nanotube (DWCNT) synthesis,electrical conductivity,nano-indentation
更新于2025-09-23 15:21:01
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PERFORMANCE PREDICTION OF BUNDLE DOUBLE-WALLED CARBON NANOTUBE-COMPOSITE MATERIALS FOR DIPOLE ANTENNAS AT TERAHERTZ FREQUENCY RANGE
摘要： In this paper, the double-walled carbon nanotube composite material (DWCNTs-composite) and bundle of DWCNT-composite material (CB-DWCNTs) for antenna applications at terahertz frequency range are presented and investigated. The mathematical modeling and analysis of DWCNTs-composite material is presented for the purpose of modelling and simulation approach. The bundle of DWCNTs-composite material is constructed and designed, based on this modeling approach. The DWCNT-composite material consists of double-walled carbon nanotube coated by a thin jacket of another di?erent material. The dependency of the electrical conductivity of B-DWCNTs-composite on di?erent parameters is presented and investigated. The performance evaluation of B-DWCNTs-composite and CB-DWCNTs materials are presented based on their electromagnetic properties. For this purpose, the dipole antennas of these composite materials are designed and implemented using CST (MWS), where the cross sections of B-DWCNTs-composite and CB-DWCNT materials are circular geometry. Furthermore, comparative studies are performed to show the dependency of size and frequency of the DWCNT-composite material. The results obtained from the DWCNTs-composite and CB-DWCNTs dipole antennas are presented based on S11 parameters, resonant frequency, gain, bandwidth, and e?ciency.
关键词： terahertz frequency,dipole antennas,electromagnetic properties,composite material,double-walled carbon nanotube
更新于2025-09-23 15:19:57