PRODUCTION OF ORIENTED CARBON NANOTUBE MEMBRANES

With the purpose of obtaining a planar deposition of a dense, thin and oriented carbon nanotubes membrane, the dielectrophoresis technique where applied using four different surfactants (SOS, SOBS, PE6400 and PE6800) in water and a solution only in 1,2-dichlorobenzene. The alignment promoted by dielectrophoresis was analyzed for each nanotube solution, regarding their quality and concentration range of dispersion capability, as a function of the variables which can affect the dielectrophoresis forces: frequency, bias and the AC/DC field ratio. The tests showed that the alignment of carbon nanotubes is characterized by its agglomeration in a "rope" shape in the gap, giving a good aligned structure. The SDBS showed the best solubilization power. However the SDS allows a better surfactant removal after alignment, PE6800 could not hold on through the centrifugation step, PE6400 does not even make a visual good dispersion and 1,2-dichlorobenzene solution showed a weak but stable capability of dispersion but terrible orientation power. Electrical measurements were coherent with the images and demonstrated the efficiency of the surfactant removal process.