Investigation of varying alkyl-chain length surfactants on iron nanoparticle sizes for magnetic particle imaging applications

Abstract

Currently, iron oxide nanoparticles around 25–30 nm in diameter are the standard magnetic tracers used for magnetic particle imaging (MPI) applications. Compared to iron oxide nanoparticles, less research has been performed in creating pure iron nanoparticles for MPI applications. Previous studies have created iron core–iron oxide shell nanoparticles around 15 nm in diameter, but in order to achieve optimal MPI signal similar to iron oxides, larger diameters around 20 nm are needed. However, due to the strong magnetic characteristics of pure iron, synthesizing pure iron nanoparticles above 15 nm in diameter can be challenging due to the high risk of agglomeration. Therefore, an investigation into creating 20-nm-sized iron nanoparticles was performed utilizing potential surfactants that might prevent agglomeration. A thermal decomposition of iron pentacarbonyl was performed with different surfactants including decylamine (DA), dodecylamine (DDA), hexadecylamine (HDA), octadecylamine (ODA), and dioctyldecylamine (DODA) to determine potential differences in size or composition. All surfactants possessed a linear structure and only varied in alkyl-chain length. From the results, it was found that longer alkyl-chain length surfactants assisted in creating larger iron nanoparticle sizes.