Synthesis and Characterization of Maghemite Nanobricks

Magnetic iron oxide nano-bricks of size range 100-700 nm were synthesized using Ferric Chloride (FeCl₃) and Ammonium Hydroxide (NH₄OH) as the precursor material in a water-in-oil microemulsion system. The as prepared ironoxide nanoplates were characterised by X-ray diraction (XRD), high resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS).

Here in we discuss a simple one pot facile protocol which allows us to prepare a large number of nano-brick structures.

Normal reverse micelles yield spherical nanoparticles, whereas one-dimensional nanotubes have been prepared using cylindrical reverse micelles, synthesized in
the presence of high concentration of FeCl₃. When aqueous FeCl₃ solution is added to the AOT/heptane mixture, the surfactants generate cylindrical micelles due to the solvation and hydrogen bonding of polar groups. FeCl₃ acts as a promoter that increases the ionic strength of a solvent and also decreases the second critical
micelle concentration of AOT. The anionic polar head groups of AOTs also have the capability to extract Fe³⁺ions from the aqueous solutions to the reverse micellar phase. As a result, iron cations concentrated in the reverse micelles are capped by the anionic groups of AOT. We decided on using this as a template to create maghemite nanorods, but serendipitously synthesized nano-bricks.