Effect of polydopamine surface modification on the phase change enthalpies of melamine foam-based phase change materials

Leveraging the advantages of high heat storage density and stable phase transition temperature, phase change materials (PCMs) have become one of the primary approaches to achieving continuous supply of renewable energy. Due to the risk of PCM leakage and poor cyclic stability, the utilization of PCMs in industry is severely limited. Generally, porous materials are used for PCM encapsulation to prevent leakage. However, due to the poor interface compatibility between porous materials and PCMs, the composite materials suffer from incomplete PCM injection and low enthalpy value. This study used polydopamine (PDA)-modified melamine foam (MF) to improve the encapsulation of polyethylene glycol (PEG) to reveal the effect of molecular modification on the thermal performance of the composite PCMs. The results indicate that with increasing PDA modification time, the adsorption capacity of MF for PEG gradually improves, the leakage of MF-based PCMs is alleviated, and the enthalpy value increases. Furthermore, by altering the molecular weight of PEG, the strengthening effect of PDA molecular modification on the heat storage capacity of MF-based PCMs is verified, and this effect is universal for polyethylene glycol materials. This study reveals that molecular modification is useful in improving the interface compatibility and heat storage capacity of the porous-based phase change composites. It fills the gap in the analysis of the influence pattern and mechanism of molecular modification on the change of phase transition enthalpy.