Innovative method of metal coating of microcapsules containing phase change materials

Microencapsulation of phase change materials (PCMs) is needed to prevent PCM leaking during melting. However, the low thermal conductivity of the microcapsules shell limits their applications. To enhance thermal conductivity of PCM microcapsules, a new method was developed for coating them with a metal using dopamine surface activation followed by electroless plating. The oxidative self-polymerization of dopamine (PDA) on the shell of the polymeric PCM microcapsules makes the surface active by providing chemisorption sites for metal deposition. Scanning electron microscope (SEM) images of the metal coated microcapsules without PDA pre-treatment did not show evidence of Ag metal on the surface of microcapsules. However, PCM microcapsules were completely covered with Ag metal when they were pre-treated with PDA as indicated by SEM and EDX tests. The enhancement in the thermal conductivity of silver coated PCM microcapsules of different size and for different silver coating coverage was investigated and discussed. This was confirmed by the enhancement in the performance of these silver-coated microcapsules using thermal cycling tests.