Thermo-optical characterization and thermal properties of graphene–polymer composites: a review

Abstract

Graphene–polymer composites have shown great promise as thermal interface materials to replace state-of-the-art silver-grease thermal pastes. A deeper understanding of their inherent thermal properties irrespective of their interfacial thermal resistivity with other systems is required to develop them with a sufficient degree of generality for a host of thermal applications. This also requires that thermal transport measurements need to be carried out contactlessly. Thermo-optical characterization methods based on the photothermal effect are valuable contactless techniques for determining the thermal properties of thin-film materials without the need to transfer heat from other media to the sample under investigation. However, they require a careful and often complex modeling procedure to extract thermal properties of the film–substrate-environment system, and the results they provide are often depending on the specific model used to interpret the measured data. In this article, we offer a review of photothermal and thermo-optical methods, with a focus on the recent progress in using them for developing the thermal properties of graphene–polymer composites. We discuss some of the methods used for aligning graphene platelets with each other, to improve their directional thermal conductivity, and to understand how thermo-optical pump–probe techniques can be used for characterizing such systems, with PEDOT:PSS–graphene composite systems as working examples.