Polyethylene Glycol/Fe<sub>3</sub>O<sub>4</sub> Nanoparticle Composite Materials: Structure, Physical Properties and Application

Abstract

Fe3O4 nanoparticles with a highly symmetric octadecahedral nanobox structure were fabricated using β-cyclodextrin as a protection agent. A series of composites (CM-1-CM-4) of polyethylene glycol (PEG) and Fe3O4 nanoparticles with different initial mass ratios were prepared using a colloid process. We found that the shape of the composites depended on the amount of Fe3O4 nanoparticles. In particular, the melting process of PEG was not only influenced by the presence of Fe3O4 nanoparticles, but also by their amount. We also noticed that the crystallinity of PEG lowered upon compositing with Fe3O4 nanoparticles, and decreased as the amount of Fe3O4 nanoparticles increased with the exception of CM-4. Interestingly, the degradation of PEG was affected by the Fe3O4 nanoparticles, leading to the appearance of different degradation products. Like the initial Fe3O4 nanoparticles, the Fe3O4 components in the composites exhibited typical soft ferromagnetism but possessed much lower saturation magnetizations. X-ray photoelectron spectroscopy (XPS) experiments revealed that electronic shift occurred from iron to oxygen. The resulting decrease in the electronic density of iron explained the observed decrease in saturation magnetizations of the composites. The composites induced strong surface-enhanced Raman scattering of organic dyes that depended on the amount of Fe3O4 nanoparticles in the composite. This study contributes to the development of composite materials combining polymers with inorganic nanoparticles.