Anisotropic Thermal Transport in Thermoelectric Composites of Conjugated Polyelectrolytes/Single-Walled Carbon Nanotubes

Cheng Kang Mai, Jun Liu, Christopher M. Evans, Rachel A. Segalman, Michael L. Chabinyc, David G. Cahill, Guillermo C. Bazan

Research output: Contribution to journalArticle

Abstract

We report a method to determine the thermal conductivities of polymer composites with single-walled carbon nanotubes (SWNTs) using time-domain thermoreflectance. Both through-plane and in-plane thermal conductivities were determined. Two types of CPEs used in these studies are of the same conjugated backbone but with either cationic (CPE-PyrBIm4) or anionic (CPE-Na) pendant functionalities. The CPE-Na/SWNT composites are p-type conductors, whereas the CPE-PyrBIm4/SWNT counterparts exhibit n-type charge transport. The CPE/SWNT films were prepared through a filtration method that preferentially aligns the SWNTs in the in-plane direction. Attaching the composites onto glass substrates with a precoated heat transducer allows one to measure the through-plane thermal conductivity of materials with rough surfaces. The in-plane thermal conductivity can be measured by embedding thick samples into epoxy followed by microtoming to expose the relatively smooth cross sections. The thermal conductivity along the in-plane direction is found to be higher than that along the through-plane direction. Indeed, the anisotropy factor of thermal conductivity in these composites is approximately an order of magnitude, favoring in-plane direction.

Original languageEnglish (US)
Pages (from-to)4957-4963
Number of pages7
JournalMacromolecules
Volume49
Issue number13
DOIs
StatePublished - Jul 12 2016

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ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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