Controlled microfluidic encapsulation of phase change material for thermo-regulation

Abstract

In this work, a facile microfluidic approach for controllable encapsulation of phase change material is presented to fabricate robust PCM capsules. The multilayer graphene is also introduced into the pure PCM (RT25) for improving the thermal conductivity of the PCM, so as to modify the thermo-regulation ability of the PCM capsules. Systematical experimental tests indicate that, via the current approach, PCM can be controllably encapsulated into every capsule with high monodispersity (coefficient of variation (C.V.) ≤ 2%) and reliable core-shell structure. The size and the core/shell proportion of the PCM capsules (i.e., the thermo-regulation ability) can be controlled precisely by adjusting the flow rates of the inner and outer phases. Especially, the thermal conductivity of PCM capsules can be improved by adding the multilayer graphene (≤ 2 wt%) with negligible degeneration of energy storage capacity less than 5%, which makes the PCM capsules response faster to the change of ambient thermal environment. The prepared PCM capsules provide new options for the real thermo-regulation and energy conservation.