Synthesis and characteristics of poly(N-isopropylacrylamide-co-methacrylic acid)/Fe3O4/poly(N-isopropylacrylamide-co-methacrylic acid) two-shell thermosensitive magnetic composite hollow latex particles

Abstract

In this study, the poly(N-isopropylacrylamide-methylacrylate acid)/Fe3O4/poly(N-isopropylacrylamide-methylacrylate acid) (poly(NIPAAm-MAA)/Fe3O4/poly(NIPAAm-MAA)) two-shell magnetic composite hollow latex particles were synthesized by four steps. The poly(methyl methacrylate-co-methylacrylate acid) (poly(MMA-MAA)) copolymer latex particles were synthesized first. Then, the second step was to polymerize NIPAAm, MAA, and crosslinking agent in the presence of poly(MMA-MAA) latex particles to form the linear poly(MMA-MAA)/crosslinking poly(NIPAAm-MAA) core–shell latex particles. Then, the core–shell latex particles were heated in the presence of NH4OH to dissolve the linear poly(MMA-MAA) core to form the poly(NIPAAm-MAA) hollow latex particles. In the third step, the Fe3O4 nanoparticles were generated in the presence of poly(NIPAAm-MAA) hollow polymer latex particles and formed the poly(NIPAAm-MAA)/Fe3O4 magnetic composite hollow latex particles. The fourth step was to synthesize poly(NIPAAm-MAA) in the presence of poly(NIPAAm-MAA)/Fe3O4 latex particles to form the poly(NIPAAm-MAA)/Fe3O4/poly(NIPAAm-MAA) two-shell magnetic composite hollow latex particles. The effect of various variables such as reactant concentration, monomer ratio, and pH value on the morphology and volume-phase transition temperature of two-shell magnetic composite hollow latex particles was studied. Moreover, the latex particles were used as carriers to load with caffeine, and the caffeine-loading characteristics and caffeine release rate of latex particles were also studied. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2880–2891