On the effective thermal conductivity of gallium-based liquid metal filled elastomers

Abstract

Gallium based alloys are liquid at ambient temperature, combining both metal-like high thermal conductivity and fluidity characteristics, which contributes to their applications in thermal management, soft robotics, stretchable electronics and etc. A great number of experimental researches have been performed in preparing Ga-based liquid metal filled elastomers (LMFEs) with various constituent systems, processing techniques, droplet morphology and filler sizes in attempt to obtain the best thermal conductive efficiency. The thermal conductive mechanisms in these LMFEs are still lacking a comprehensive understanding up to date, and therefore the present work aimed to conduct a thorough analysis on this topic using both theoretical models and finite element method (FEM) simulations. The predictability of four classic micromechanics models was compared with the experiments and FEM simulations, and their relevant thermal conductive principles were identified from the simulated thermal flux evolution. Some deficiencies of these analytical models are identified and amended by reconsidering their special architectures. This work is favorable for establishing a general and quantitative relationship between the effective thermal conductivity and microstructures for most of the synthesized LMFEs available in the literatures.