Block copolymer mediated stabilization of sub-5 nm superparamagnetic nickel nanoparticles in an aqueous medium

The paper presents a facile method for decreasing the size of water dispersible Ni nanoparticles from 30 nm to 3 nm by the incorporation of a passivating surfactant combination of pluronic triblock copolymer and oleic acid into a wet chemical reduction synthesis. A detailed study revealed that the size of the Ni nanoparticles is critically governed not only by the concentration of the tri block copolymers but also dependent on the hydrophobic nature of the micelle-core formed. The synthesized Ni nanoparticles were thoroughly characterized by TEM, XRD, XPS and temperature and field dependent magnetic measurements along with a comprehensive FTIR analysis to predict a possible mechanism of formation.