Preparation and Crystallization Behavior of Sensitive Thermochromic Microencapsulated Phase Change Materials

We investigated the formation of sensitive thermo-chromic microcapsules with inorganic/organic shell-layer-embedded polyesters for thermal properties, thermo-chromic performance, and crystallization behavior of ethyl myristate (EM) in confined spaces. In this paper, As the reaction proceeded, the aminated silica (NH2-SiO2) nanoparticles modified in the aqueous phase and isophorone diisocyanate (IPDI) in the oil phase gradually self-assembled at the inner interface, leading to the formation of an inorganic/organic polymers composite shell. The effect of NH2-SiO2 nanoparticles content on the crystallization behavior, microstructure, morphology, and phase-change properties as well as the thermal stability of MPCMs were investigated in detail. Interestingly, the covalent attachment of NH2-SiO2 nanoparticles on the capsules surface offered long-term chemical stability rather than, traditional physical adsorption. The NH2-SiO2 nanoparticles were found distributed uniformly on the surface of MPCMs, and the onset crystallization temperature of MPCMs increased by 7.33 °C with NH2-SiO2 nanoparticles addition of 15% content, which counteracts the super-cooling phenomenon. Microcapsule temperature change optical microscopy and non-isothermal crystallization kinetics revealed that the crystallization of RS-MPCMs was homogeneous as well.