Dispersion of carbon nanotubes by the branched block copolymer Tetronic 1107 in an alcohol–water solution

The dispersion of carbon nanotubes (CNTs) by the branched block copolymer Tetronic 1107 was investigated in mixed solvents consisting of water and one of the following alcohols: ethanol, n-propanol, ethylene glycol (EG), or glycerol (GLY). The maximum concentration of dispersed CNTs (C _limit) and the optimum T1107 concentration (C _opt) to disperse the maximum amount of CNTs in different solvents were obtained from UV–vis–NIR absorbance spectra. The addition of ethanol or n-propanol to water dramatically increases the C _limit. The value of C _opt follows the order: n-propanol–water > ethanol–water > EG–water ≈ GLY–water mixtures. I _D/I _G was used to characterize the defect density of CNTs dispersed in the mixed solvents, which was investigated by Raman spectroscopy. The I _D/I _G values in n-propanol–water and ethanol–water mixtures are higher than those in EG–water and GLY–water mixtures. High-resolution transmission electron microscopy is used to confirm a favorable dispersion in the presence of different alcohols.