Thermoelectric Behavior of Carbon Nanotube Filled Polymer Nanocomposites
Y.S. Kim, D. Kim, C. Yu, J.C. Grunlan
Texas A&M University, US
Keywords: thermoelectric, Carbon Nanotube, Segregated Network
Abstract:In this study, we demonstrate that polymer nanocomposites can be viable for light-weight and economical thermoelectrics. Segregated network concept was adapted in order to reduce the amount of CNTs to achieve high electrical conductivity, and poly(vinyl acetate) emulsion polymer was used as a matrix to create the segregated network of conductive fillers. During drying, relatively large polymer particles force fillers to reside interstitial space between polymer particles. This situation dramatically reduces the space available for the conductive filler to form conductive networks, which results in a significant enhancement of electrical conduction with a small amount of electrically conductive filler. The electrical carrier transport occurring through low-dimensional fillers such as nanotubes or nanowires also plays a role in increasing thermopower and keeping thermal conductivity low. We observed that high electrical conductivity can be obtained while maintaining low thermal conductivity, which is very close to the intrinsic thermal conductivity of the polymer. In the case of 20 wt% CNT polymer composite films made of PVAc matrix, a thermoelectric figure of merit was measured to be 0.006 at room temperature (approaching that of silicon).