Synthesis of magnetic nanostructures: Shape tuning by the addition of a polymer at low temperature

•Low-temperature method for iron oxide (Fe3O4 and γ-Fe2O3) nanostructures is described.•Shape of iron oxide nanostructures can be tuned by varying the reaction parameter.•Needle- and flower-shaped iron oxide nanostructures are obtained with polymer.•HRTEM analysis shows iron oxide nanostructures are crystalline in nature.•Both γ-Fe2O3 and Fe3O4 nanostructures shows superparamagnetic behavior.

We report a simple method for shape-controlled synthesis of iron oxide spinels such as magnetite (Fe3O4) and maghemite (γ-Fe2O3) nanostructures using a thermoresponsive polymer poly(vinyl methyl ether) (PVME) by the alkaline hydrolysis of iron salt at low temperature (20 °C). Microscopic analysis confirmed the formation of needle- and flower-shaped iron oxide nanostructures depending on reaction conditions. High-resolution transmission electron microscopic analysis of the needle- and flower-shaped nanostructures as well as their corresponding selected area electron diffraction patterns revealed that the formed nanostructures are crystalline in nature. X-ray diffraction study reveals the formation of well-crystalline pure Fe3O4 and γ-Fe2O3 nanostructures under different reaction conditions. Fourier transform Infra-red spectroscopic analysis confirms the adsorption of PVME on the surface of iron oxide nanostructures. Finally, the magnetic properties of γ-Fe2O3 and Fe3O4 nanostructures is studied that shows the superparamagnetic behavior of the formed iron oxide nanostructures.

Graphical abstractA simple method for shape-controlled synthesis of iron oxide spinels such as magnetite (Fe3O4) and maghemite (γ-Fe2O3) nanostructures using a thermoresponsive polymer poly(vinyl methyl ether) (PVME) by the alkaline hydrolysis of iron salt at low temperature (20 °C) is described.Figure optionsDownload full-size imageDownload as PowerPoint slide