Copper Encapsulated Vertically Aligned Carbon Nanotube Arrays

A new procedure is described for the fabrication of vertically aligned carbon nanotubes (VACNTs) which are decorated, and even completely encapsulated by a dense network of copper nanoparticles. The process involves the conformal deposition of pyrolytic carbon (Py-C), to stabilize the aligned carbon nanotube structure during processing. The stabilized arrays are mildly functionalized using oxygen plasma treatment to improve wettability, and then infiltrated with aqueous, super-saturated Cu-salt solution. Once dried, the salt forms a stabilizing crystal network throughout the array. After calcination and H₂ reduction, Cu nanoparticles are left decorating the CNT surfaces. Studies were carried out to determine the optimal processing parameters to maximize Cu content in the composite. These included duration of Py-C deposition, system process pressure, and implementation of subsequent and multiple Cu-salt solution infiltrations. The optimized procedure yielded a nanoscale hybrid material where the anisotropic alignment from the VACNT array was preserved, and the mass of the stabilized arrays was increased by over 24 times due to the addition of Cu. The procedure has been adapted for other Cu-salts and can also be used for other metal salts altogether including Ni, Co, Fe, and Ag. The resulting composite is ideally suited for application in thermal management devices due to its low density, mechanical integrity, and potentially high thermal conductivity. Additionally, further processing of the material via pressing and sintering can yield consolidated, dense bulk composites.     Read the Full Paper