Evaluation of Theoretical Models for Determining Effective Thermal Conductivity and Interfacial Thermal Resistance of Carbon Nanotube Polydimethylsiloxane Nanocomposites

Abstract

Thermal conductivity is an important parameter for many industrial applications of nanocomposites. Carbon nanotube nanocomposites often have measured thermal conductivity well below expected values. Some models have been proposed that consider the unique structure of nanocomposites to predict their effective thermal conductivity. These models include the nanoparticles’ interfacial thermal resistance, aspect ratio, and volume fraction. In this work, the thermal conductivity of multiwalled carbon nanotube (MWCNT) polydimethylsiloxane nanocomposites has been studied and the thermal conductivity and interfacial thermal resistance in a polymer matrix have been estimated using suitable models. Nanocomposites made using CNTs with an aspect ratio <100 were found to be below the percolation threshold at 3.5% loading. In situ, the thermal conductivity of MWCNTs was estimated to be 412 ± 252 W m^–1 K^–1 and interfacial thermal resistance was estimated at an R_K of 6.6 ± 0.3 × 10^–8 m² K W^–1.