Bio-Based Radish@PDA/PEG Sandwich Composite with High Efficiency Solar Thermal Energy Storage

Phase change materials with desirable light-thermal conversion ability are particularly attractive for solar energy harvesting and storage. Herein, we demonstrate that the combination of efficient light-thermal conversion, excellent thermal property, and reliability can be achieved via the construction of a novel form-stable phase change composite material, that is, Radish@PDA/PEG with a sandwich structure. A 3D porous structure derived from radish via freeze-drying is adopted as the substrate; then, self-polymerization of dopamine is initiated in the surface of Radish to produce a layer of polydopamine (PDA). Finally, polyethylene glycol (PEG) impregnation via vacuum infusion is applied to form the Radish@PDA/PEG composite. These results prove that the incorporation of interlayer PDA can not only improve the strength of the porous structure to protect the PEG from leakage, but also enhance the encapsulation capacity of PEG and light absorption ability of the composite. The preparation method is based on common biomass with green chemicals and thus provides a general way to prepare eco-friendly and biodegradable composite with promising applications in light thermal energy management.