Dynamic electrical properties of polymer-carbon nanotube composites: Enhancement through covalent bonding
Composite formation between carbon nanotubes and polymers can dramatically enhance the electrical and thermal properties of the combined materials. We have prepared a composite from polystyrene and multi-walled carbon nanotubes (MWCNT) and, unlike traditional techniques of composite formation, we chose to polymerize styrene from the surface of dithiocarboxylic ester-functionalized MWCNNs to fabricate a unique composite material, a new technique dubbed "gRAFT" polymerization. The thermal stability of the polymer matrix in the covalently linked MWCNT-polystyrene composite is significantly enhanced, as demonstrated by a 15 °C increase of the decomposition temperature than that of the noncovalently linked MWCNT-polystyrene blend. Thin films made from the composite with low MWCNT loadings (<0.9 wt%) are optically transparent, and we see no evidence of aggregation of nanotubes in the thin film or solution. The result from the conductivity measurement as a function of MWCNT loadings suggests two charge transport mechanisms: charge hopping in low MWCNT loadings (0.02-0.6 wt%) and ballistic quantum conduction in high loadings (0.6-0.9 wt%). The composite exhibits dramatically enhanced conductivity up to 33 S m-1 at a low MWCNT loading (0.9 wt%). © 2006 Materials Research Society.
Publication Source (Journal or Book title)
Journal of Materials Research
Curran, S., Zhang, D., Wondmagegn, W., Ellis, A., Cech, J., Roth, S., & Carroll, D. (2006). Dynamic electrical properties of polymer-carbon nanotube composites: Enhancement through covalent bonding. Journal of Materials Research, 21 (4), 1071-1077. https://doi.org/10.1557/jmr.2006.0129