Preparation of acrylic PCM microcapsules with dual responsivity to temperature and magnetic field changes

Abstract

Energy preservation is one of the serious concerns in recent years to reduce fossil fuels consumption and greenhouse gases. Magnetic microcapsules based on n-hexadecane/Fe3O4 core and poly methyl methacrylate (PMMA) shell were designed as an innovative type of dual-functional phase change materials. Fe3O4 nanoparticles were first synthesized by co-precipitation method and then modified with oleic acid. Then, they were incorporated into suspension polymerization in the presence of MMA and n-hexadecane. FTIR and SEM analyses confirmed the presence of all components in the magnetic microcapsules with a wrinkled morphology and uniform size in averagely 180 µm. They revealed reasonable thermal storage properties and high thermal cycling performance according to DSC thermograms. The encapsulation efficiency and thermal storage ability were calculated by the extracted data from DSC analysis for all the samples and their thermal conductivities were measured too. Magnetometry studies approved superparamagnetic properties of the obtained microcapsules with low remanence and coercivity. With such a dual-functional feature, the introduced magnetic microcapsules could show potential applications in some high-tech fields with providing both thermal regulating and magnetic responsive properties.