γ-Fe2O3 oriented growth by surfactant molecules in microemulsion

Surfactant-assisted route to fabricate CoFe2O4 individual nanoparticles and spherical assemblies

“…The surfactant is recognized to play a fundamental role, since the formation of spherical aggregates is observed in all the samples when the surfactant elimination is not complete. This observation is consistent with the literature [46,47], which reports that, as the concentration of the surfactant increases relatively to the particle concentration, the formation of ordered structures appears to be favoured in respect to the formation of individual particles. In this context, the surfactant residue still present in the samples (which do not undergo the successful elimination) favors the aggregation of the primary particles, inducing the formation of a wormlike pores structure inside the spherical aggregates.…”

Controllable synthesis and magnetic properties of pure hematite and maghemite nanocrystals from a molecular precursor

“…The remanences (M r ) and coercive forces (H c ) of the ␣-Fe 2 O 3 nanorods prepared at 180 • C for 1.5 h were 1.6 × 10 −3 emu/g and 31 Oe, respectively; while those of the ␣-Fe 2 O 3 nanocubes prepared at 180 • C for 12 h were 6.1 × 10 −4 emu/g and 10 Oe, respectively. It was suggested that the higher M r and H c of the ␣-Fe 2 O 3 nanorods may be associated with their higher aspect ratio, because shape anisotropy would exert a tremendous influence on their magnetic properties, such as the lower saturation magnetization, as well as the increased remanence and coercive force [21,30]. However, the M r were almost zero and the H c were very low, so we think that both of the rodlike and cubiform ␣-Fe 2 O 3 nanocrystals were superparamagnetic.…”

Characterization of iron hydroxide/oxide nanoparticles prepared in microemulsions stabilized with cationic/non-ionic surfactant mixtures

“…9. The pictures show an agglomerate of many (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) single crystals. This agglomerate exhibits oval-shaped (or elongated) clumps which encounter a clear sintering upon calcination.…”

“…Iron oxide nanoparticles (haematite, maghemite, magnetite) can be prepared by different methods such as sol-gel [13], precipitation [14], microwave synthesis [15], hydrothermal synthesis [16], microemulsion [17][18][19]. Here we report a water-in-oil microemulsion route to synthesize iron oxide nanoparticles.…”