Significantly Enhanced Single-Walled Carbon Nanotube Dispersion Stability in Mixed Solvent Systems

Research on the dispersion of pristine single-walled carbon nanotubes (SWCNTs) is mostly focused on measuring the dispersion limit in various organic solvents, yet little attention has been paid to the dispersion stability of SWCNTs in viable organic solvents. We have studied SWCNT dispersion stability for mixtures of the organic solvents N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidinone (NMP). Our results show that mixing DMF and NMP can yield dispersion stabilities that are 60-115% greater than the pure solvents with a 50/50 mixture (v/v). SWCNT aggregation is described by a physical model that combines the Maxwell-Boltzmann energy distribution function and DLVO theory for quantitative comparison between solvent systems.