Dispersion of Carbon Nanotubes

Yurekli K, Mitchell CA, Krishnamoorti R (2004) Small-angle neutron scattering from surfactant-assisted aqueous dispersions of carbon nanotubes. J Am Chem Soc 126 9902-9903. 

In general, de-aggregation and dispersion of carbon nanotubes are provided by magnetic stirring, shear mixing, reflux, or, most commonly, ultrasonication. Sonication can be provided in... 

The dispersion of carbon nanotubes in PU matrix can also be affected by the synthetic methods as well as the tensile stress etc. Xiong et al. found that the CNTs in the composites after tensile testing could easily take an ordered orientation along with the tensile direction on the cross-section perpendicular to the pressure direction, whereas the arrangement of the CNTs has not almost changed on the cross-section parallel to the pressure direction (62). The phenomenon that the SWNTs near the film substrate interface are driven to self-organize to a more ordered structure was discovered by Chen et al. (16). 

The gap between the predictions and experimental results arises from imperfect dispersion of carbon nanotubes and poor load transfer from the matrix to the nanotubes. Even modest nanotube agglomeration impacts the diameter and length distributions of the nanofillers and overall is likely to decrease the aspect ratio. In addition, nanotube agglomeration reduces the modulus of the nanofillers relative to that of isolated nanotubes because there are only weak dispersive forces between the nanotubes. Schadler et al. (71) and Ajayan et al. (72) concluded from Raman spectra that slippage occurs between the shells of MWNTs and within SWNT ropes and may limit stress transfer in nanotube/polymer composites. Thus, good dispersion of CNTs and strong interfacial interactions between CNTs and PU chains contribute to the dramatic improvement of the mechanical properties of the... 

Wise [2] prepared selected polyimides, (I), that formed dispersions of carbon nanotubes exhibiting long-term stability. Nanocomposites produced from these dispersions were useful in the fabrication of lightweight aerospace structures. 

Zhang J, Wang Q, Wang L, Wang A (2007) Manipulated dispersion of carbon nanotubes with derivatives of chitosan. Carbon 45 1911-1920... 

Tsai YC, Chiu CC, Tsai MC, Wu JY, Tseng TP, Wu TM, Hsu SP (2007) Dispersion of carbon nanotubes in low pH aqueous solutions by means of alumina-coated silica nanoparticles. Carbon 45 2823-2827... 

Ionic Liquids-Assisted Dispersion of Carbon Nanotubes in Water... 

Zhou XS, Wu TB, Han BX et al (2009) The dispersion of carbon nanotubes in water with the aid of very small amounts of ionic hquid. Chem Commun 14 1897-1899... 

Battisti, A., Skordos, A.A., and Partridge, I.K. 2009a. Monitoring dispersion of carbon nanotubes in a thermosetting polyester resin. Compos. Sci. Technol. 69 1516-1520. 

Sesis A, Hodnett M, Memoli G, Wain AT, Jurewicz I, Dalton AB, Casey JD (2013) Influence of acoustic cavitation on the controlled ultrasonic dispersions of carbon nanotubes. J Phys ChemB 117 15141-15150... 

Uddin, N. M., Capaldi, F. M., Farouk, B. (2011). Molecular dynamics simulations of the interactions and dispersion of carbon nanotubes in polyethylene oxide/water systems. Polymer. 52(2), 288-296. 

N. Puech, E. Grelet, P. Poulin, C. Blanc, P. van der Schoot, Nematic droples in aqueous dispersions of carbon nanotubes. Phys. Rev. E 82, 20702-1-4 (2010)... 

Bratcher, M.S., Gersten, B., Kosik, W., Ji, H., Mays, J., A Study in the Dispersion of Carbon Nanotubes, Proceedings of e Materials Research Society, Fall 2001. 

M.L Polo-Luque, B.M. Simonet, M. Valcarcel, Functionalization and dispersion of carbon nanotubes in ionic hquids. Trends in Analytical Chemistry, 47, 99-110, 2013. 

Songmin et al. reported the preparation of chitosan hydrochloric acid salt and the effect in improving the dispersion of carbon nanotubes in different solvents and silicone rubber. It was also found that treated carbon nanotubes could be dispersed in the silicone rubber homogeneously based on SEM and XRD analysis. The incorporation of carbon nanotubes enhanced the thermal stability of the silicone rubber. They also significantly improved the mechanical properties of the silicone rubber matrix. From the FTIR spectra, it was befieved that chitosan hydrochloric acid salt adsorbed on the surface of the carbon nanotube and then interacted with silicone rubber matrix, resulting in the enhancement of dispersion of carbon nanotubes, improving thermal and mechanical properties in the resulting nanocomposites [124]. 

Y.Y. Huang, E.M. Terentjev, Dispersion of carbon nanotubes mixing, sonication, stabilization, and composite properties. Polymers 4 (2012) 275. 

P, del Rio, R., Yanez, C., Ferreyra, N.F., Rivas, G.A., and Bollo, S. (2012) Effect of the dispersing agent on the electrochemical response of glassy carbon electrodes modified with dispersions of carbon nanotubes. Electroanalysis, 24, 2317-2323. 

Ji, Y Huang, Y. Y. Tajbakhsh, A. R. Terentjev, E. M., Polysiloxane Surfactants for the Dispersion of Carbon Nanotubes in Nonpolar Organic Solvents. Langmuir 2009, 25,12325-12331. 

Due to the van der Waals interaction, the nanotubes tend to aggregate to form bundles or ropes and further agglomerate when dispersed in the polymer matrix. The high surface area of the nanotubes also results in a high viscosity of the nanotube/polymer mixture particularly when fabricating the nanocomposite with high loading level of the nanotubes, which makes the dispersion of the nanotubes extremely difficult. The dispersion of carbon nanotubes in the polymer matrix can be made by several techniques. 

For melt-compounded nanocomposites, the screw rotation speed of an extruder has a large influence on the dispersion of carbon nanotubes in the polymer matrix. Chen et al employed an ultrahigh-shear extruder to mix pristine MWNTs with PVDF pellets at a screw speed of 1000 rpm (1470 [62]. For the purpose of comparison, the MWNT/PVDF... 

Grady B P (2010) Recent developments concerning the dispersion of carbon nanotubes in polymers, Macromol Rapid CommMn 31 247-257. 

Esawi A M K, Salem H G, Hussein H M and Ramadan A R (2010) Effect of processing technique on the dispersion of carbon nanotubes within polypropylene carbon nanotube composites and its effect on their mechanical properties, Polym Compos 31 772-780. 

Etika K C, Cox M A and Grunlan J C (2010) Tailored dispersion of carbon nanotubes in water with pH-responsive polymers. Polymer 51 1761-1770. 

Rana S, Karak N, Cho JW, Kim YH. Enhanced dispersion of carbon nanotubes in hyperbranched polyurethane and properties of nanocomposites. Nanotechnology November 2008 19 495707 (8 pp.). 

Vaisman, L.,Wagner, H.D. Marom, G. (2006). The role of surfactants in dispersion of carbon nanotubes. Advances in Colloid and Interface Science, 128-130, 37-46. 

Fig. 3 Aqueous dispersion of carbon nanotubes 2 hours after sonication in an ultrasonic bath, (1) pristine MWCNT (2) MWCNT functionalized with carboxylic groups (3) MWCNT functionalized with hydroxyl groups...

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