Development of phase change materials directly encapsulated within gold shell microcapsules for flexible intelligent textile with energy storage and photo-thermal conversion ability

Conventional liquid-solid phase change materials (PCMs) are usually susceptible to leaking at high temperatures. To address the leaking of PCMs, gold (Au) shell microcapsules with a PCM core (PCM core-Au shell microcapsules) have been prepared by directly coating the impermeable Au film onto emulsions containing octadecane, eicosane or coconut oil core. Au shell with different thickness have been coated on the emulsion surface to achieve a stable microcapsule structure and high phase change enthalpy. The melting enthalpy of PCM core-Au shell microcapsules ranges from 70 to 144 J/g. No obvious leaking of liquid PCMs during the heating process is observed. By adsorbing the PCM core emulsions to pre-cationized cotton textiles and subsequently electroless plated Au film onto the emulsion surface, flexible cotton samples with PCM core-Au shell microcapsules are successfully prepared. The adsorption efficiency of emulsion to the cotton samples reaches 20 % by immersing the sample into a 0.3 vol% emulsion suspension for 2 h. The temperature distribution test shows that the PCM core-Au shell microcapsules coated samples have an obvious latent heat storage and release behaviour during the heating and cooling processes. Additionally, 63 % photo-thermal conversion efficiency has been achieved for octadecane core-Au shell microcapsules coated samples due to the Plasmonic localised heating of Au NPs. At ambient or cool environments, PCM core-Au shell microcapsules coated samples always reach a higher temperature with a faster temperature increase rate on the sample surface and the skin surface simulated by a tubing coil filled with 37℃ water.