Preparation and characterization of n-octadecane @ calcium fluoride microencapsulated phase change materials

Microencapsulation of phase change materials (PCMs) with functional shell materials such as luminescent material could endow the obtained microencapsulated PCMs (MPCMs) with improved latent heat storage properties. The PCM core in turn could protect the luminescence shell from large temperature shifting and thus improve its performance. In this work, a series of MPCMs derived from n-octadecane (ODE) core and CaF2 shell were synthesized via a self-assembly method. The effects of the preparation conditions, including the core/shell mass ratio, the dosage of the emulsifier (styrene-maleic anhydride copolymer, SMA) and the dosage of the chelator (Na(3)Cit), on the properties of the prepared ODE@CaF2 MPCMs were investigated and the optimal preparation condition was obtained. The MPCM obtained according to the optimal procedure (MPCM1) exhibited an encapsulation ratio of 54.02% and a latent heat of 131 J/g with negligible leakage. It also possessed excellent thermal reliability and significantly improved thermal conductivity. The MPCM1 could not only be utilized as good latent heat storage material and thermal regulation material, but also provided one new idea to prevent the thermal quenching of luminescence materials. In addition, this work could shed some light on the high-value utilization of recovered fluorine resources.