Abstract:

The sunscreen microcapsules were prepared by interfacial free-radical polymerization, with poly （ethylene glycol） dimethacrylate （PEGDMA） as shell material and the mixture of homosalate （HMS）, avobenzone （AVB） and octocrilene （OCT） as core material. The morphologies of PEGDMA microcapsules prepared at different core composition and with different amounts of shell were explored by optical microscope （OM）. The chemical structure, particle size distribution and the morphology of microcapsules were characterized by FT-IR, particle size & zeta potential analyzer （Nano-zs） and scanning electron microscope （SEM）, respectively. The thermal stability of microcapsules and encapsulation efficiency were obtained by thermogravimetric analysis （TGA）. The values of sun protection factor （SPF） of microcapsules were measured on a UV transmittance analyzer. The results show that when m（AVB） ∶m（OCT） ∶m（HMS）=1∶2∶3 in the core, and the mass concentration of PEGDMA （the material for building shell） is 6%, the microcapsules thus prepared will have a spherical morphology, indicative of an encapsulation efficiency of 73.55%. Moreover, the sunscreen microcapsules lead to obviously higher SPF values compared with the naked mixture of HMS, AVB and OCT in sunscreen creams.

Key words: sunscreen, microcapsule, homosalate, avobenzone, octocrilene, coating