Separation of surfactant functionalized single-walled carbon nanotubes via free solution electrophoresis method

Central European Journal of Physics (Impact Factor: 1.08). 04/2011; 9(2):325-329. DOI: 10.2478/s11534-010-0083-z

ABSTRACT This work presents the application of the free solution electrophoresis method (FSE) in the metallic / semiconductive (M/S)
separation process of the surfactant functionalized single-walled carbon nanotubes (SWCNTs). The SWCNTs synthesized via laser
ablation were purified through high vacuum annealing and subsequent refluxing processes in aqua regia solution. The purified
and annealed material was divided into six batches. First three batches were dispersed in anionic surfactants: sodium dodecyl
sulfate (SDS), sodium cholate (SC) and sodium deoxycholate (DOC). The next three batches were dispersed in cationic surfactants:
cetrimonium bromide (CTAB), benzalkonium chloride (BKC) and cetylpyridinium chloride (CPC). All the prepared SWCNTs samples
were subjected to FSE separation process. The fractionated samples were recovered from control and electrode areas and annealed
in order to remove the adsorbed surfactants on carbon nanotubes (CNTs) surface. The changes of the van Hove singularities
(vHS) present in SWCNTs spectra were investigated via UV-Vis-NIR optical absorption spectroscopy (OAS).


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    ABSTRACT: This paper describes techniques for rapidly producing a carbon nanotube thin film by electrophoretic deposition at room temperature and determines the film mass density and electrical/mechanical properties of such films. The mechanism of electrophoretic deposition of thin layers is explained with experimental data. Also, film thickness is measured as a function of time, electrical field and suspension concentration. We use Rutherford backscattering spectroscopy to determine the film mass density. Films created in this manner have a resistivity of 2.14×10- 3 Ω∙cm, a mass density that varies with thickness from 0.12 to 0.54 g/cm3, and a Young’s modulus between 4.72 and 5.67 GPa. The latter was found to be independent of thickness from 77 to 134 nm. We also report on fabricating free-standing films by removing the metal seed layer under the CNT film, and selectively etching a sacrificial layer. This method could be extended to flexible photovoltaic devices or high frequency RF MEMS devices.
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