Carbon Nanotubes and Nanocomposites for Electrical and Thermal Applications

Abstract

The extraordinary electrical and thermal properties of individual carbon nanotubes have prompted predictions on their potentials for ultimately forming polymeric nanocomposites. A significant barrier for the predicted nanocomposites is the severe bundling and insolubility of carbon nanotubes. Chemical modification and functionalization have been demonstrated as being effective in the debundling and solubilization of carbon nanotubes for their homogeneous dispersion into polymer matrices for desired high‐quality nanocomposites. More elegant is the approach to use polymers that are structurally identical or maximally similar to the matrix polymers in the nanotube functionalization to ensure full compatibility of the functionalized nanotubes with the corresponding polymer matrix. Several representative examples are presented, along with discussion on the benefits and issues concerning the polymeric nanocomposites thus obtained. For superior electrical properties, there is experimental evidence suggesting that the nanotube dispersion in the polymer matrix plays an important role. More promising is the use of separated metallic carbon nanotubes for a much enhanced performance in conductive nanocomposites and in related applications, such as transparent conductive films. For highly thermal conductive polymeric nanocomposites, on the other hand, the feasibility of using carbon nanotubes to achieve the desired performance has yet to be convincingly demonstrated experimentally. Nevertheless, the available results do suggest significant effects of the nanotube dispersion and alignment on thermal conductivities of the nanocomposites.

Light-weight nanocomposite materials with enhanced thermal transport properties

“…Theoretical and experimental results on the extremely high thermal conductivity in individual carbon nanotubes have promoted extensive effort in the research community on the development of polymeric/carbon nanotube nanocomposites for superior thermal transport performance [7,8,20,21] . Generally speaking, however, the predicted or expected dramatically enhanced thermal transport in polymers upon the incorporation of carbon nanotubes has not been realized, with the resulting nanocomposites exhibiting thermal conductivity values only in single digitals of the W/mK unit even at very high nanotube loadings [21] .…”

“…A variety of experimental strategies have been developed and practiced for the incorporation of carbon nanotubes into polymeric matrices to target the resulting nanocomposite materials for superior thermal transport performance. The relevant activities and signifi cant results have been reviewed in several articles and book chapters [20,21] . Generally speaking, polymeric composites with dispersed carbon nanotubes have been rather disappointing in terms of their harnessing the extreme thermal conductivities found in individual carbon nanotubes for metal-like thermal conductivity.…”