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

作者：Mai Cheng Kang; Liu Jun; Evans Christopher M; Segalman Rachel A; Chabinyc Michael L; Gahill David G; Bazan Guillermo C

来源：Macromolecules, 2016, 49(13): 4957-4963.

DOI：10.1021/acs.macromol.6b00546

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-PyrBIm(4)) or anionic (CPE-Na) pendant functionalities. The CPE-Na/SWNT composites are p-type conductors, whereas the CPE-PyrBIm(4)/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.

• 出版日期2016-7-12