Morphology Control in the Synthesis of Iron Oxide and Oxyhydroxide Nanoparticles

Precise control of size and shape are important goals in the synthesis of functional nanoparticles, as these factors play a key role in determining properties. Morphology control in the formation of iron oxide and oxyhydroxide nanoparticles can be approached in a number of ways, and this presentation outlines some of the approaches that have been explored in recent work at the Nanochemistry Research Institute. In some cases, control of nanostructure and particle aggregation characteristics can be achieved by simple control of supersaturation conditions, while in others, crystal morphology is modified by the face-selective action of organic additives. For example, the effect of polyphosponates on hematite nanoparticle morphology has been studied under both acidic and basic conditions and the experimental results interpreted in conjunction with molecular modelling studies of the crystal surface/additive interaction. Crystal growth mechanisms in the formation of iron oxide and oxyhydroxide nanoparticles have also been studied, providing examples of some novel, tube-like morphologies and evidence for growth of larger assemblies by oriented aggregation of nanoparticulate sub-units