KCS

Surface modification of carbon nanotubes (CNTs) has recently attracted a great deal of attention, because the surface characteristics considerably affect applications of CNTs in the fields of biomedical applications, biosensors, catalysts supports, and composites. Wettability of CNTs by liquids is one of the most important surface properties, which normally expressed by contact angle. It is believed that the contact angle of CNTs is determined by chemical composition and surface roughness. Single-walled Carbon Nanotubes (SWNTs) grown on textured Si surfaces by chemical vapor deposition method are Superhydrophobic as the hierarchical structures created by nanostructures on microstructures. The acid oxidation using an acid mixture of nitric and sulfuric acid can readily change the surface of SWNTs grown on textured Si surfaces from superhydrophobic to superhydrophilic. And the reduction by heating in NH3 environment at an elevated temperature can reverse the surface state from superhydrophilic to superhydrophobic. In conclusion, the wettability of SWNTs are controlled by the oxidation and reduction process, significantly facilitate the fabrication and application of composites containing CNTs.