In this study, the electrical properties of carbon nanotubes (CNTs) assembled into different architectures
using the layer-by-layer technique have been investigated. The CNTs were modified with
either anionic water-soluble polyaniline blend poly(sodium 4-styrenesulfonate) (PANI-PSS) or cationic
poly(diallydimethyl ammonium chloride) (PDADMAC) to form negatively charged CNT− and positively
charged CNT+. PANI-PSS was synthesized by interfacial polymerization of aniline using PSS as template.
The first of the three architectures studied was assembled by the LbL deposition of anionic CNT− and
cationic CNT+ while the two others were prepared by the deposition of only 1 type of CNTs (CNT+ or CNT−)
with an oppositely charged polyelectrolyte to form PDADMAC/CNT− and PANI-PSS/CNT+
.
The thickness
and surface roughness of the three different films were characterized by atomic force microscopy (AFM)
while the electrical and optical properties were measured using a four points probe setup and a UV–vis
spectrophotometer, respectively. The dispersion of the CNTs using PANI-PSS as capping agent was the
least efficient when compared to the PDADMAC leading to a lower adsorption on a charged substrate.
Interestingly, the layer-by-layer deposition of the CNT−/CNT+ films had a slower growth but displayed a
superior electrical conductivity when compared to the other two architectures.