Achieving ultra-high concentration CNT dispersion by cationic perylene bisimide-based dispersant

Carbon nanotubes (CNT) have a strong tendency to aggregate, which seriously affects the doping homogeneity in the preparation of CNT-based composites. Using dispersant is essential for dispersing CNT, however, conventional dispersants typically suffer low efficiency. Herein, a cationic perylene bisimide (CPBI)-based dispersant, which featured with a large conjugated center, is synthesized. Owing to the strong π-π interaction between the conjugated center of CPBI and CNT, and the hydrophilic multiple protonated N atoms, the dispersant shows excellent performance for stabilizing CNT in water. Ultra-high concentration CNT dispersion (40 mg mL −1 ) is achieved by tip-sonication with the assistance of CPBI at a weight ratio of 1:1 (CPBI-to-CNT), which is superior to most of that reported previously. Remarkably, CNT dispersion is maintained even at a CPBI-to-CNT weight ratio of 1:3. The homogeneity and stability of the dispersion is systematically characterized by dynamic light scattering (DLS), Tyndall effect, scanning electron microscopy (SEM), and zeta potential test. The dispersion also exhibits film-forming properties and has been successfully used to prepare solvent-resistant and conductive CNT coatings (128.7 S/m). In addition, CNTs are dopped into PVA matrix, effectively enhance the tensile strength for about 102 % at a PVA-to-CNT weight ratio of 100:3.