Carbon nanotubes coating dispersion

Dieckmann et al. in 2003 described an amphiphilic a-helical peptide specifically designed to coat and solubilize CNTs and to control the assembly of the peptide-coated nanotubes into macromolecular structures through peptide-peptide interactions between adjacent peptide-wrapped nanotubes [227]. They claimed that the peptide folds into an amphiphilic a-helix in the presence of carbon nanotubes and disperses them in aqueous solution by noncovalent interactions with the nanotube surface. EM and polarized Raman studies revealed that the peptide-coated nanotubes assemble into fibers with the nanotubes aligned along the fiber axis. The size and morphology of the fibers could be controlled by manipulating the solution conditions that affect peptide-peptide interactions [227]. 

Dielectric percolative composites have been synthesized [95]. The materials are based on sulfonated PEEK and multi-walled acidified carbon nanotubes coated with poly(aniline). The multi-walled acidified carbon nanotubes are modified by an situ polymerization technique. This method is useful to achieve eventually a good dispersion of the carbon nanotubes... 

Jin et al. (65) used poly(vinylidene fluoride) (PVDF) as a compatibilizer to assist dispersion of CNTs in PMMA. Multi-walled carbon nanotubes were first coated with PVDF and then melt-blended with PMMA. Poly(vinylidene fluoride) served as an adhesive to improve wetting of CNTs by PMMA and to increase the interfacial adhesion resulting in improved mechanical properties of MWCNT-PMMA composites. 

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... 

Pure metals as well can be deposited on the surface of carbon nanotubes. The reductive precipitation of gold nanoparticles on MWNT coated with citrate ions may be given just as one example. Besides dispersing the MWNT, the citric acid is also responsible for the reductive generation of the gold particles from HAuCLt. Other metals like platinum, palladium, titanium, and iron can be deposited on the nanotube surface, too. 

In in-situ polymerization, nanoscale particles are dispersed in the monomer or monomer solution, and the resulting mixture is polymerized by standard polymerization methods. This method provides the opportunity to graft the polymer onto the particle surface. Many different types of nanocomposites have been processed by in-situ polymerization. Some examples for in-situ polymerization are polypyrrole nanoparticle/amphiphilic elastomer composites magnetite coated multi-walled carbon nanotube/polypyrrole nanocomposites and polypyrrole/ silver nanocomposites. The key to in-situ polymerization is appropriate dispersion of the filler in the monomer. This often requires modification of the particle surface because, although dispersion is easier in a liquid than in a viscous melt, the settling process is also more rapid. 

Recently [Sangermano et al., 2008] reported for the first time the paeparation of antistatic epoxy coatings via cationic UV curing of an epwxy resin in the presence of a very low content of carbon nanotubes (CNT). After dispersing the CNT into the epexy resin, in the range between 0.025-0.1 wt.-%, the formulations were cured by means of UV light in the presence of a sulfonium salt as cationic photoinitiator. 

Zou, J., Chen, H., Chunder, A., Yu, Y., Huo, Q., Zhai, L. Preparation of a superhydrophobic and conductive nanocomposite coating from a carbon-nanotube-conjugated block copolymCT dispersion. Adv. Mater. 20, 3337 (2008)... 

Experimental design and performance analysis of alumina coatings deposited by a detonation spray process Adjustment of the band gap energies of biostabilized CdS nanoparticles by application of statistical DoE Experimental design and optimization of dispersion process for single-walled carbon nanotube bucky paper... 

Surfactants are added to a thermoset resin system to promote the dispersion of fillers in the resin matrix. Recently, surfactants have been used to disperse carbon nanotubes in polymer matrices [48-50]. Surfactants are of two types neutral and ionic. Surfactants have many applications in coating industries for the development of a water-based resin system [51]. Surfactants are added to phenolic or polyurethane foam formulation in which they facilitate formation of small bubbles. The size and uniformity of bubble formation results in a fine cell structure. A surfactant reduces the surface tension of resin formulations and provides an interface between the highly polar resin and the non-polar blowing agent. The surfactant for a particular resin system must be selected carefully so that it is compatible with the resin and resistant... 

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