Stable Suspension of Crystalline Fe₃O₄Nanoparticles from In Situ Hot-Fluid Annealing

Abstract

Crystalline Fe3O4 nanoparticles were prepared via chemical precipitation in reverse micellar cavities in a microemulsion, followed by in situ thermal annealing of the microemulsion at 150 °C. A valuable feature of the annealing is that the physical properties of the nanoparticles are preserved in the crystallization process, and the resulting crystalline Fe3O4 nanoparticles remain in stable suspensions. The method thus allows the control of average sizes in the final crystalline nanoparticles by varying the initial microemulsion parameters. Results from the characterization of the nanoparticle samples are presented and discussed.

In vitro DNA binding, molecular docking and antimicrobial studies on a newly synthesized poly(o-toluidine)–titanium dioxide nanocomposite

“…where the pronounced peak for POT is expected at 2q ¼ 25 appears in POT-TiO 2 nocomposite suggesting the presence of POT. The average crystallite size of the POT and POT-TiO 2 nanocomposite were calculated using the values of FWHM 27,28 and were found to be in the range of 20-30 nm. The relative crystallite size of POT and POT-TiO 2 has been found to be in the order of POT < POT-TiO 2 indicating that TiO 2 nanoparticles signicantly inuence the crystallite size of POT matrix in POT-TiO 2 nanocomposite which may be possibly due to the polymerization of o-toluidine (OT) monomers adsorbed on the surface of TiO 2 encapsulating TiO 2 nanoparticles.…”

Synthesis of Nearly Monodisperse Iron Oxide and Oxyhydroxide Nanocrystals

“…[23,33] As studied by other groups, goethite is believed to form via a dissolution and crystallization process, that is, dissolution of the amorphous intermediate phase followed by the precipitation of goethite, while magnetite is believed to be formed via a dehydration in situ and subsequent local rearrangement. [33][34][35][36] In neutral and acidic conditions, the solubility of the intermediate phase increases…”

“…pH 8) the solubility of the intermediate phase is very low, and the dissolution-crystallization process is completely inhibited so that the transformation can only proceed by a dehydration in situ and local rearrangement, leading to magnetite. [33][34] The solubility of the intermediate phase is much higher at lower concentrations of NaOH (0.2 g, ca. pH 5) so that the transformation can proceed more easily via the dissolution-crystallization process, thus, leading to the goethite phase.…”

Study of viscoelastic properties of magnetic nanofluids: an insight into their internal structure

“…Magnetic nanouids (MFs) are functional materials with great potential in many industrial 1,2 and biomedical applications. 3,4 They are usually prepared by dispersing nanosized ferromagnetic or ferrimagnetic nanoparticles like Fe 2 O 3 , Fe 2 O 4 , CoFe 2 O 4 , Fe, etc.…”