Emulsifying ability and cross-linking of silk fibroin microcapsules containing phase change materials

The microencapsulation of phase change materials (PCMs) with regenerated silk fibroin (SF) as a shell by means of SF self-assembling was studied. Nonionic, ionic and mixed surfactants were applied to increase the emulsion stability and enhance encapsulating capacity of SF microcapsules. Effects of different types of surfactants on diverse properties of PCM microcapsules including morphology, energy storage density, mechanical strength and thermal stability have been investigated. It was observed that mixed surfactants promoted significantly the formation and stability of n-octadecane/SF emulsion. With the effects of co-emulsifiers, mixed surfactants acted simultaneously as excellent emulsifiers and cross-linkers in SF microencapsulation processing. Adding mixed surfactants to n-octadecane/SF system improved the surface morphology and energy storage density, along with the mechanical strength.