Thermoelectric technology includes a renewable energy technology, is that converts heat directly into electricity without any displacement member. Compared with the inorganic thermoelectric materials, polymeric material having much potential advantages of low toxicity, light weight, low thermal conductivity, etc, which has attracted wide attention. Single-walled carbon nanotubes (SWCNTs) is a one-dimensional material, due to its high charge mobility, excellent chemical stability and mechanical strength,it's widely used in flexible electronic components. Pure SWCNTs generally exhibit p-type charge transport, namely air oxidation. Complementary n-type can be achieved by doping composite polyethyleneimine (PEI) or a small molecule with multiple electronic unit.

Recently, Cheng-Kang Mai and Guillermo C. Bazan from the University of California and Jun Liu from North Carolina State University, published a joint report a method that a time domain heat reflection to determine the thermal conductivity of the polymer and SWCNTs single-walled carbon nanotube composite material.

The researchers successfully measured the thermal conductivity perpendicular to the plane direction of the plane direction. Two types of CPEs used in the study with the same conjugated backbone, but one has an anionic (CPE-PyrBIm4) side chain functional groups and the other has a cation (CPE-Na) side chain functional groups. CPE-Na / SWCNT is a p-type semiconductor, while the CPE-PyrBIm4 / SWCNT exhibit n-type charge transport. CPE / SWCNT film is prepared by means of a filtration process, nanotubes preferentially oriented in a plane direction. On a glass substrate containing a composite material previously coated with heat sensors used to measure the surface roughness of the material thermal conductivity perpendicular to the plane direction. Plane thermal conductivity in the direction of the thickness of the sample can be embedded in epoxy resin, the relatively smooth microtome cross-section is exposed is measured.

The study found the plane direction perpendicular thermal conductivity higher than the thermal conductivity in the plane direction. In fact, the anisotropy factor of these composites thermal conductivityis is almost in the same order of magnitude, and the orientation of thermal conductivity in the planar direction is prior to in a vertical direction priority.

Hongwu International Group LTD sells purest and cheapest Carbon Nanotubes(SWCNTs, DWCNT, MWCNT) in the world. Carbon nanotubes  are available with different purity grades and surface functionalization. Carbon Nanotubes is produced by Chemical Vapor Deposition (CVD) method by HWNANO and depending on the diameter one can obtain either single-walled Carbon Nanotubes(SWCNTs) or multi-walled Carbon Nanotubes (MWCNTs). Our current capacity for the production of MWCNTs far exceeds that of other suppliers.

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by Corrine