An effective compound thermal diffusivity characterization method for polymer nanocomposites

Abstract

Polymer composites with layered structures are easily prepared and applied for a range of potential applications due to their excellent thermal properties. This introduces significant demands to characterize the thermal properties of these nanocomposites. In this study, we report an effective compound thermal diffusivity characterization method to predict and furthermore to help regulate the thermal diffusivity of polymer nanocomposites. As a case study, an improved nanoporous template wetting technique was employed to fabricate 20 nm and 200 nm high-density polyethylene (HDPE) nanowires within porous anodic alumina (AAO) substrates. A compound thermal diffusivity model for double-layer structural nanocomposite is proposed to predict the effective overall thermal diffusivity of the HDPE/AAO samples. An infrared sequence transformation technique was introduced for measurement verification. The theoretically predicted results are in accordance with the experimental results, where the in-plane thermal diffusivity of the AAO substrate was reduced by 34.7% and 41.7%, respectively, from 20 nm and 200 nm HDPE nanowire arrays fabrication. The characterization results also revealed that the thermal diffusivity of the polymer nanocomposites could be quantitatively regulated via adjusting the polymer content, which could potentially provide a theoretical basis for thermal management and thermal structure design.