Block Copolymer Assisted Carbon Nanotube Dispersion in Saturated Hydrocarbons

Many of CNT's great applications require well-dispersed CNT in a certain media, but the tubes tend to bundle with each other due to the strong intertube van der Waals interaction. Research has been carried out to disperse CNT in polar solvents and aromatic non-polar solvents, with the assistance of surfactants and/or polymers. However, good dispersion of CNT in saturated hydrocarbon media has not yet been reported.

Here we report a block copolymer (BCP) assisted non-covalent method to disperse CNT in saturated hydrocarbons. A styrene-butadiene block copolymer (PS-b-PBD) was chosen to help the CNT dispersion because of the good compatibility between the styrene block and the CNT, and between the butadiene block and the solvent. Detailed research showed that this PS-b-PBD could help CNT to disperse in saturated hydrocarbons only when it forms micelles in the solvent. The star micelles with PS as the core and PBD as the corona could accommodate as much as 100 mg/L CNT in a hexane solvent. The CNT-BCP complex is very stable and would not dissociate upon sonication or dilution. After removing the solvent, the CNT-BCP complex forms a rubber-like film, and this material is readily re-dispersed in saturated hydrocarbon solvents.