Development of a novel transparent substrate coated by carbon nanotubes through covalent bonding

There is considerable investigation into the applications of carbon nanotubes because of their valuable properties. In this study, we succeeded in poly-carboxylation of multi-walled carbon nanotubes (CNTs) tethered to a glass substrate through covalent bonding. By causing a carboxylation reaction using a peroxide derivative, we were able to observe many carboxyl groups on the surfaces of CNTs. We characterized the obtained CNTs derivatives using Infrared and Raman spectroscopy. The CNTs reacted directly with glass substrates that presented amino groups, and the tethered CNTs were not removed from the substrate by sonication, suggesting the formation of a strong bond between the CNTs and substrate. Nanostructures in the shape of curled individual strings were observed using a scanning electron microscope and an atomic force microscope. The transparency of substrates was more than 97% in visible regions.