Tuning the composition and morphology of carbon nanotube-copper interface

Carbon nanotube (CNT)-copper nanocomposites are promising materials for light-weight high-ampacity conductors. The key issue in hybridization of CNT and metal is creating a strong bonding between them. This requires proper modification of the CNT surface. However, experimental works on determining the effect of interfacial functionalization on the properties of the metal/CNT system is scarce. In this paper, the effect of CNT surface modification on the morphology, interfacial interactions, and electrical properties Cu/CNT hybrid system is investigated. For this purpose, CNTs with carboxyl, thiol, and nitrogen doped surface groups were used as substrate for growth of Cu particles via a facile electrochemical process. It is observed that not only the morphology but also the chemical state of the Cu deposits are affected by the surface functional group on CNT. Thiol group significantly enhances copper wettability towards CNT, facilitating a uniform deposition of copper, and impedes oxidation. Also, Cu/CNT thin films fabricated via vacuum filtration that contain thiol-activated CNTs shows four and seven times higher electrical conductivity compared with systems that contain carboxyl and N-doped surface groups, respectively.