Polymer/Fe3O4 Composite Nanofibers

Magnetic NPs have been receiving increased attention with the rapid development of nanotechnology.Among them, Fe3O4 NPs have caused widespread interest owing to their high superparamagnetism as well as facile preparation. Their easy oxidation and resulting decline in magnetic property is a problem, however, which is effectively solved by the dispersion of Fe3O4 NPs in polymer nanofibers. The simplest way to prepare polymer/Fe3O4 composite nanofibers is to disperse Fe3O4 NPs in the polymer solution and subsequently carry out the electrospinning process. Xin et al. successfully fabricated poly(p-phenylene vinylene)/Fe3O4 composite nanofibers via electrospinning of a precursor solution and subsequent thermal conversion (Fig. 3.14A). In addition, the aligned nanofibers can be obtained by employing two parallel magnets as the collector. A variety of polymer/ Fe3O4 composite nanofibers, including PAN/Fe3O4 composite nanofibers, gelatin/Fe3O4 composite nanofibers, etc., have been reported by means of a similar method, and their potential applications in various fields have been studied as well.

FexOy (Iron Oxide) Nanofibers

It is generally known that iron oxides mainly contain Fe2O3 and Fe3O4. Fe2O3 is stable in air, and possesses potential applications in adsorption, sensors, electrochemical catalysis, and other fields. On the other hand, Fe3O4 is a typical kind of magnetic material, which can be applied in magnetofluid as well as magnetic recording materials. Fe2O3 nanofibers with uniform structure can be easily prepared via an electrospinning technique followed by a calcination treatment (Fig. 3.6A). For example, Gao et al. prepared hollow a-Fe2O3 nanofibers via such a strategy and developed their potential in dye adsorption. Similarly, Nalbandian et al. found that electrospun Fe2O3 nanofibers possess promising prospects in heavy metal removal. Guo et al. studied the effect of the structure of electrospun Fe2O3 nanotubes on gas sensing; the results indicated that porous a-Fe2O3 nanotubes exhibited remarkably enhanced performance for acetone sensing over hollow a-Fe2O3 nanotubes. g-Fe2O3 nanofibers have also been successfully synthesized and their properties as acetone gas sensors have been found as well.