Dispersions of High-Quality Carbon Nanotubes with Narrow Aggregate Size Distributions by Viscous Liquid for Conducting Polymer Composites

Abstract

Preserving the quality of carbon nanotubes (CNTs) is essential to fully utilize the characteristics in dispersions and other forms. To fabricate CNT dispersions retaining the quality, we propose to reduce CNT aggregate size distributions by viscous liquids at the initial stage from as-grown CNT powders originally possessing a wide aggregate size distribution. Higher viscosity solvents were found to highly disentangle the CNT powder and give a narrower CNT aggregate size distribution without impairing the quality. To show the advantages of these CNT dispersions, we demonstrated a 10 4 -fold increased electrical conductivity of CNT rubber composite based on the predispersion step of CNT powder in the rubber base compound with high viscosity. Our method can afford a high quality of CNT and avoid a long, heavy dispersion, which was conventionally carried out to decrease entangled, large size CNT aggregates, furthermore, applicable for fabrication of conducting polymer composites.

Liquid Crystalline Behaviors of Single-Walled Carbon Nanotubes in an Aqueous Sodium Cholate Dispersion

“…A two-step process was employed to disperse the SWCNT powder. The first step was predispersion by a high-viscosity solvent . The second step involved homogenization by sonication.…”

“…The first step was predispersion by a high-viscosity solvent. 22 The second step involved homogenization by sonication. In the first step, 100 mg of SWCNT powder and 100 mL of glycerol (Wako) were stirred for 18 hours at 500 rpm (AS ONE, HPS-100PD).…”

Quantitative Surface Characterization of As-Grown and Acid-Treated Single-Walled Carbon Nanotubes: Implications for Functional Materials

“…To expose the surfaces of as-grown CNTs to a basic solution, the CNT powder was beforehand exfoliated in a viscous liquid of glycerol under a mild agitation (a stir bar, 500 rpm, 24 h) by the predispersion approach we recently developed. 55 The glycerol solvent of the resultant CNT dispersion was replaced by a basic aqueous solution, and then, the titration was done by an aqueous solution of hydrochloric acid. To measure the acidic functional groups, solutions containing NaHCO 3 (pK a 6.4) or NaOH (pK a 15.7) were used.…”

“…To apply the method, wetting CNT surfaces with a basic solution is essential to titrate by an acidic one for precise evaluation. To expose the surfaces of as-grown CNTs to a basic solution, the CNT powder was beforehand exfoliated in a viscous liquid of glycerol under a mild agitation (a stir bar, 500 rpm, 24 h) by the predispersion approach we recently developed . The glycerol solvent of the resultant CNT dispersion was replaced by a basic aqueous solution, and then, the titration was done by an aqueous solution of hydrochloric acid.…”

Applications of Photoinduced Phenomena in Supramolecularly Arranged Phthalocyanine Derivatives: A Perspective

“…In both cases the attitude of the carbon nanotubes to aggregate was overcome using the π-electron cloud of Pc that interacts with the π-electrons of CNTs enhancing their solubility. This approach is often preferred to the covalent functionalization of the carbon nanotubes since the covalent approach can induce important modifications to electronic and spectroscopic features of CNTs [39,111,112]. In an another system [113] ZnPc derivative was coupled with CNTs by means of the use of a pyrene (magenta colored in Figure 19) functionalized with the imidazole entity.…”