Liquid metal capsules for autonomic thermal energy control

Abstract

This research is focused on the ultrasonic encapsulation of low temperature GaIn eutectic alloy using silica nanoparticles as a Pickering shell. GaIn eutectic has a solid/liquid transition temperature at 15.7 °C and can be used for autonomic heat uptake and release as a phase change material (PCM). The best solvent for ultrasonic encapsulation of GaIn is chloroform resulting in capsules of 1.4 µm possessing a silica nanoshell which are stable for at least 5 years. Differential scanning calorimetry confirmed the heat uptake/release performance during at least 50 thermal cycles. GaIn capsules were incorporated into porous Al/Mg light weight alloy used in the aerospace industry for autonomic control of its surface temperature. Capsules demonstrated an effective decrease of the alloy surface temperature from 82 °C to 30 °C during infrared heating of the samples. Compared to other PCMs, encapsulated liquid metals have the advantages of high electric and thermal conductivity, low melting temperature and immiscibility with usual solvents. They can be used as autonomic micro and nano containers in aerospace or electronic industries.