The SWNTs Are Selectively Dispersed By Using Triphenylamine Polyimide And Polypropionic Silane

DC arc discharge method is relatively mature technology to prepare.Single-walled carbon nanotubes(SWNTs)with varying helix angles and different diameters.From the viewpoint of the electrical properties,the as-prepared SWNTs are composed of metallic and semiconducting species.Aim at the efficient enrichment and isolation of SWNTs with sole electrical conductivity,the bundles of SWNTs should be effectively dispersed in some kind of solvent into individual ones with the assistance of some dispersion agents,and then it is possible to enrich and isolate metallic or semiconducting SWNTs by ultracentrifugation through the chemical recognition between SWNTs and dispersing agents,laying a solid foundation for the applications of SWNTs in the field of electronics,magnetics,optics,etc.Crude samples containing SWNTs were largely prepared by DC arc discharge method,and SWNTs with high purity and good dispersibility were obtained through successive mechanical grinding,heat treatment,mixed acid oxidation,polar solvent dispersion and ultracentrifugation.The polyimide polymer with side chain of triphenylamine was synthesized,and applied as a dispersing agent to the selective dispersion of SWNTs.UV-vis-NIR absorption spectra and Raman spectra demonstrated that this kind of polyimide had selective dispersibility towards semiconductor SWNTs with small chiral angles.Polymethyl(crylic acidyl)silane were synthesized,and applied as another dispersing agent to the selective dispersion of SWNTs.UV-vis-NIR absorption spectra and Raman spectra demonstrated that this kind of polysilane had selective dispersibility towards metallic SWNTs.From the results of infrared and ultraviolet spectra combined with theoretical analyses,it is concluded that aromatic polyimides with the side chain of triphenylamine recognize selectively with semiconducting SWNTs mainly by the ?-? interaction,and polymethyl(crylicacidyl)silane recognize selectively with metallic SWNTs mainly by special CH-? interactions.