Polymethyl(1-Butyric acidyl)silane-Assisted Dispersion and Density Gradient Ultracentrifugation Separation of Single-Walled Carbon Nanotubes.

Individual single-walled carbon nanotubes (SWNTs) with distinct electronic types are crucial for the fabrication of SWNTs-based electronic and magnetic devices. Herein, the water-soluble polymethyl(1-butyric acidyl)silane (BA-PMS) was synthesized via the hydrosilylation reaction between 3-butenoic acid and polymethylsilane catalyzed by 2,2'-azodibutyronitrile. As a new dispersant, BA-PMS displayed a quite good dispersing capacity to arc-discharged SWNTs and moderate selectivity for metallic species. The application of sucrose-DGU, the density gradient ultracentrifugation with sucrose as the gradient medium, to the co-surfactants (BA-PMS and sodium dodecyl sulfonate) individually dispersed SWNTs yielded metallic SWNTs of 85.6% purity and semiconducting SWNTs of 99% purity, respectively. This work paves a path to the DGU separation of the SWNTs dispersed by polymer-based dispersants with hydrophobic alkyl chains.