pH Responsive Behavior of Fe₃O₄@PDEA-PEGMA Core-Shell Hybrid Magnetic Nanoparticles

Abstract

Fe₃O₄@PDEA-PEGMA core-shell magnetic nanoparticles were prepared via surface-initiated atom transfer radical polymerization (ATRP). First, an ATRP initiator was immobilized onto the surface of Fe₃O₄ magnetic nanoparticles, then poly[2-(diethylamino)ethyl methacrylate] (PDEA) and poly(poly[(ethylene glycol) monomethacrylate]) (PEGMA) were grafted from the surface of the magnetic nanoparticles in succession. Each step of the reactions gave distinctive thermogravimetric analysis curves. Polymer shells cleaved from Fe₃O₄ core were measured by gel permeation chromatography, while its molecular weight was found to increase with successive polymerization (with a polydispersity of approximately 1.3–1.4). The architecture of the core-shell nanoparticles was confirmed by transmission electron microscopy. The Fe₃O₄@PDEA-PEGMA hybrid magnetic nanoparticles formed stable dispersions in H₂O at low pH (pH < 6) and precipitated out at high pH (pH > 6). This pH transition behavior was also observed in dynamic light scattering experiments.

Keywords:

• ATRP
• block copolymers
• core-shell
• magnetic nanoparticles
• pH responsive

Notes

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