Paraffin@silica@poly(dopamine)/Silver Phase Change Microcapsules with Efficient Photothermal Conversion Performance

In order to improve the photothermal conversion ability of phase change materials, Ag and polydopamine (PDA) were loaded onto the surface of paraffin@silicon dioxide (Pn@SiO₂) microcapsules. The system starts with the encapsulation of paraffin into the silica shell using sodium silicate as the silica precursor. Then PDA is deposited on the silica shell, and the reduced Ag nanoparticles are uniformly immobilized on the microcapsule surface by the reducing property of PDA. The obtained Pn@SiO₂@PDA/Ag microcapsules showed a regular spherical morphology as well as the desired chemical composition. The antileakage property of the microcapsules was significantly improved by coating the surface of the microcapsules with PDA, and the leakage rate was reduced from 4.86 to 1.27%. With the increase of silver content on the surface of microcapsules, their thermal conductivity and photothermal conversion performance properties are substantially improved. The results showed that the silver-plated microcapsules prepared with potassium sodium tartrate as the reducing agent not only had excellent antimicrobial properties but also had a high photothermal conversion efficiency of 88.7%. The work provides a promising approach for the development of functional materials based on phase change materials by loading Ag and PDA on phase change microcapsule systems, with potential applications in solar energy products, smart fabrics, and biomedical therapeutics.