Thermoelectric composites based on carbon nan otubes and micro-glass bubbles

Abstract

In this study, carbon nanotubes (CNTs) and micro glass bubbles (μ-GBs) have been incorporated into a polymer matrix to impart thermoelectric properties. The purpose was to create segregated CNT network by using μ-GBs as voids that "push" the CNTs into confined to spaces and to form more tightly bound yet uniformly distributed conductive network. CNTs and μ-GBs were dispersed in a nylon-formic acid solution using horn sonication followed by coagulation in deionized water, and nanocomposite panels were fabricated using a hot press. The design of experiments technique was employed to design and analyze the experiments. Factors included CNT concentration, μ-GB concentration, and μ-GB size. Thermal and electrical conductivities and Seebeck coefficient of the composite panels were measured from 20 to 50°C, from which the figures of merit (z Ts) were calculated. It was found that zTs are affected by all the factors with varying degrees, and zT as high as 0.0548 was achieved, which is one of the highest values obtained with polymer-based thermoelectric materials.