Tannic acid directed synthesis of Fe3O4@TA@P(NVP-co-NIPAM) magnetic microspheres for polyphenol extraction

Abstract

In this study, a novel core-shell structured Fe3O4@TA@P(NVP-co-NIPAM) magnetic microsphere has been successfully developed for polyphenol extraction employing tannic acid (TA) directed copolymerization. The TA directing strategy guided copolymerization preferentially on the surface of the magnetic core and facilitated formation of the shell for coating the magnetic core. It was unveiled that the amount of TA, the ratio of the two monomers, and the amount of surfactant were critical for the preparation of the magnetic microspheres. The identity and proportion of the shell were analyzed by FT-IR and TGA. Magnetic hysteresis loop measurement confirmed the superparamagnetic nature and no loss of magnetization after coating. The prepared magnetic microspheres demonstrated outstanding absorption ability to typical polyphenols. Kinetic studies suggested that the adsorption behavior followed Langmuir absorption model. The developed magnetic microspheres should be useful for biological studies. The TA directing strategy would be valuable for synthesis of core-shell structured particles.