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 1524 XIA Juan et al.: PEG/Fe3O4 Nanoparticle Composite Materials: Structure, Physical Properties and ApplicationNo.7 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.
The formation of a 1:1 supramolecular complex between β-cyclodextrin (β-CD) and 18crown-6 (18C6) by simply mixing them was confirmed by elemental analysis, 1 H nuclear magnetic resonance (1 H NMR) and electrospray ionization mass spectrometry. The probable interaction sites between these species were determined by two-dimensional rotating frame nuclear Overhauser effect spectroscopy (ROESY), which showed that 18C6 tended to be located on the narrow end of the cavity of β-CD. Also, the degradation process including the degree of degradation and the degradation products of the complex was carefully compared with those of β-CD and 18C6 through thermogravimetric analysis and gas chromatography coupled to time-of-flight mass spectrometry. The experimental data indicated that the presence of 18C6 resulted in an earlier degradation of β-CD. Furthermore, the relative abundance of larger fragments from the degradation process of the two components was reduced drastically because of an intermolecular interaction. These results strongly indicate that a supramolecular complex can be constructed using the flexible macrocyclic molecule 18C6 as a guest and the rigid macrocyclic molecule β-CD as the host via molecular assembly between them.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.