Surfactant Free Room Temperature Synthesis of Iron Oxide Magnetic Nanoparticles in Microchannels

摘要

We present a one pot surfactant free, room temperature synthesis technique to produce individual magnetic nanoparticles (MNP) in a microfluidic environment. A two phase co-flow approach using chemical precursors was adopted to synthesize magnetite (Fe_3O_4) nanoparticles in microchannels. This method prevents aggregation and promotes narrow size distribution. The flow rate could be used to control the size and shape of the MNP. X-ray diffraction studies reveal the formation of the magnetite phase. Structural and morphological analysis using transmission electron microscopy shows that the MNP size and shape could be tuned in the range of 12 nm (sphere) to 31 nm (cube). The saturation magnetization was 84 emu/g for 12 nm spheres compared to 74 emu/g for 31 nm cubes. This synthesis process can be used to synthesize "bare" magnetite nanoparticles and extended to other oxides by changing the precursors.