Selective thiolation of single-walled carbon nanotubes

Single-walled carbon nanombes (SWCNTs) were derivatized with thiol groups at the ends of the nanotubes. The carbon nanotubes (CNTs) were treated with acid mixtures and modified through a series of chemical reactions. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy were used to verify the intermediate products of the oxidation and reduction reactions and the final products. The thiolated CNTs were adsorbed on micron-sized silver and gold particles as well as gold surfaces to study the interaction between the thiol groups of the nanotube and the noble metals. The thiol-metal adhesion was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), wavelength dispersive electron spectroscopy, and Raman spectroscopy. A new type of bonding between the CNT and a noble metal surface was proposed that involves a bow-type single-walled nanotube (SWNT) with its two ends strongly attached to the metal surface. (C) 2003 Elsevier B.V. All rights reserved.