copper nanotubes, which can be made up of single-walled or multiwalled carbon atoms, have exceptional properties as individual materials. They are tensile stronger than steel, have high conductivity and are excellent thermal dissipators. They also exhibit resistance to corrosion and fatigue, making them ideal materials for a number of applications such as energy devices and sensors.
Cu/carbon nanotube (CNT) composites are touted to substitute copper in a wide range of applications [8-17] because of their superior mechanical, electrical and thermal properties. However, despite many promising results, these Cu/CNT composites have not been able to achieve overall performance surpassing that of copper and are unlikely to be practical for real-world use.
Reducing CNT agglomeration: The presence of CNT agglomerates in the Cu matrix has been observed to reduce composite hardness, strength and wear properties, especially at low CNT vol% fabricated mainly by powder-processing. This is attributed to a phase separation between Cu and CNT grains in the resulting microstructure.
Improved CNT-Cu interfacial interaction: Ensuring strong, effective CNT-Cu interfacial interactions is critical to enhance stress transfer and electron/phonon transport in Cu/CNT composites. This is challenging because the two metals exhibit different surface chemistry, poor affinity to each other and high mobility.
Enhancing CNT-Cu interfacial interaction can be achieved by improving CNT template hydrophilicity or by adding oxygen-containing groups to the CNT templates for facilitating wetting by aqueous Cu electrolytes. Oxygen-functionalized templates have been reported to result in lower agglomeration and better tensile properties than non-functionalized Cu/CNT wires produced by electrodeposition without anodization pre-treatment.