Synthesis of magnetic particles with well-defined living polymeric chains via combination of RAFT polymerization and thiol-ene click chemistry

Abstract

Magnetic polymer particles have attracted large attention, due to their potential applications in biomedical field such as drug delivery, protein adsorption, magnetic resonance imaging and etc. A combinatorial method based on reversible addition fragmentation chain transfer (RAFT) polymerization and thiol-ene click chemistry was adopted to synthesize magnetic core-shell polymer hybrids. Well-defined poly (N-isopropylacrylamide) with trithiocarbonate moieties (PNIPAAm-CTA) was designed by RAFT polymerization and then was reduced to thiol-end polymers (PNIPAAm-SH). On the other hand, the magnetic particles (Fe3O4) were prepared by hydrothermal method, modified with silane coupling agent (KH-550) and acrylic acid to introduce vinyl group (−CH = CH2) onto the inorganic surface. Then the Fe3O4-g-PNIPAAm particles were synthesized by using thiol-ene click chemistry. The chemical composition, surface morphology, core-shell structure were characterized by a series of techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), dynamic light scattering (DLS) and vibrating sample magnetometer (VSM). The results showed that the as-synthesized composite iron oxide particles owned thermoresponsive behaviors and superparamagnetic properties. And, the superparamagnetic thermoresponsive particles with high magnetization might be potential ideal candidates for biomedical field.