Magnetite nanowires are of interest in nano-optoelectronics and nanomedicine due to their unique magnetic and optoelectronic properties. A simple, reproducible synthesis method would enable research into possible nanowire applications. In particular, one-dimensional nanoscale materials have recently been shown to exhibit enhanced cellular endocytosis for nanoscale theranostic drug delivery applications. Magnetite is an attractive nanowire material; it exhibits a net ferrimagnetic moment naturally at room temperature, is a strongly correlated material, and is biologically compatible. This project replicates a published method of synthesizing magnetite nanowires for use in many possible applications. The synthesis is a hydrothermal method published by Farraz et al. in 2008, which uses PEG as a surfactant to constrain the direction of crystal growth. It produces high purity monocrystalline, single-domain wires with a high aspect ratio. Powder X-ray diffraction, energy-dispersive X-ray spectroscopy, and selected-area electron diffraction are used to characterize phase and crystal structure. A successful replication of the synthesis method produces wires tens of nanometers in diameter and microns in length. Initial EDS analysis shows mainly iron and oxygen elements, indicating little contamination. XRD should show single-phase Fe3O4 with FCC structure and a lattice constant around 8.404Å. The absence of a peak indicating the (221) plane would confirm that the phase is not maghemite. SAED measurements will be correlated with XRD and SEM measurements to confirm crystallite size, and d-spacing information will help positively identify phase. Simple, repeatable synthesis can produce high purity monocrystalline magnetite nanowires with properties ideal for optoelectronic, magnetic, and nanomedicine applications.
Surfactant-Assisted Hydrothermal Synthesis of Magnetite Nanowires
Saturday, October 29, 2011
Hall 1-2 (San Jose Convention Center)