Ag ion decoration for surface modifications of multi-walled carbon nanotubes

Abstract

The production of high performance metal matrix composites depends on a proper design of the surface of the reinforcing phase, ensuring a good contact with a metal phase. In the present work, two Ag decorating procedures to modify the surface of multi-walled carbon nanotubes (MWCNT) were evaluated for further production of aluminum matrix composites. The procedures consisted in a two steps route based on acid oxidation of carbon nanotubes (CNT) followed by suspension in an Ag ion solution; and a single step route, based on the effect of n-dimethylformamide (DMF) as an activation agent of CNT surface, in presence of Ag ions. Transmission and scanning-transmission electron microscopy, Raman and Fourier-transformed infrared spectroscopy were employed in order to characterize the results. The two steps route resulted in Ag nano-particles homogeneously deposited over the CNT surface. The mechanism for the deposition is based on carboxyl and probably hydroxyl functional groups formed in the first step, acting as nucleation sites for Ag precipitation in the second step. The single step route resulted in the formation of sub-micrometric Ag particles heterogeneously mixed to CNT bundles.

Keywords

• carbon nanotubes
• Ag decoration
• acid refluxing
• surface activation