Reinforcement and shape stabilization of phase-change material via graphene oxide aerogel

Phase change materials (PCMs) are of interest in many applications which may require shape stabilization. In this study, a graphene oxide aerogel (GOxA) reinforced paraffin PCM composite is developed, effectively reinforcing and shape-stabilizing the paraffin. The molecular and diffraction characterizations suggest that the GOxA network potentially affects paraffin's crystallization. The mechanical characterizations using durometer and nanoindentation show that the composite is 3 similar to 7x harder than pure paraffin and maintains significant strength even above paraffin's melting temperature. Moreover, the composite is much less strain-rate sensitive than paraffin. The reinforcement via GOxA is much beyond the prediction by the rule-of-mixture, implying a strong GOxA-paraffin interfacial bonding. To our best knowledge, this is the first study on the mechanical behavior of paraffin and GOxA-PCM composite, providing critical insights into their behavior. Additionally, the relationship between the hardness and durometer index first-ever developed here will enable the quantitative durometer testing on materials for many other applications at different ambient conditions due to its versatility and simplicity. (C) 2016 Elsevier Ltd. All rights reserved.