Organic Solvent-Redispersible Isolated Single Wall Carbon Nanotubes Coated by in-Situ Polymerized Surfactant Monolayer

The dispersion of single wall carbon nanotubes (SWNTs) in solvents and their processability are of importance for various practical applications of SWNTs but have not been fully achieved yet. Here, we report the homogeneous and stable dispersion of individually isolated SWNT in alcohols using surfactant-aided noncovalent functionalization. This is the first utilization of surfactants for the dispersion of SWNTs in alcohols. The functionalized SWNT (p-SWNTs) were fabricated by in-situ free radical polymerization of cationic surfactants, cetyltrimethylammonium 4-vinylbenzoate, covering the surface of SWNTs in water, followed by freeze-drying to obtain in powder form. The p-SWNTs are highly dispersible in alcohols such as ethanol, methanol, 1-butanol, and 1-propanol by simple vortex mixing or mild sonication and mostly exist as individually isolated nanotubes. The in-situ microstructures of the p-SWNTs dispersed in alcohols were measured with small-angle neutron scattering, which shows an encapsulation of SWNTs with a swollen polymerized surfactant layer. After the p-SWNT dispersions in alcohols were completely dried, the p-SWNTs are still readily redispersible in alcohols, indicating good stability of the polymerized surfactant monolayer of p-SWNTs in alcohols.