Clustering of magnetic nanoparticles with and without magnetic field
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Date
2019-06
Authors
Nur Syazwani Binti Rohisham
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Abstract
Bare iron oxide nanoparticles and surface functionalized iron oxide nanoparticles with Poly(diallyldimethylammoniumchloride) (PDDA) sample was prepared at three different concentrations of 50 ppm, 100 ppm and 200 ppm. The presence of PDDA as surface coating provides electrosteric stabilization for the particles which causes steric repulsion among the particles. This lowers the rate of aggregation of magnetic iron oxide nanoparticles and less particles clustering event is observed. The main purpose of this study is to investigate the clustering of magnetic iron oxide nanoparticles with and without magnetic field. An external magnetic field is introduced by using a permanent magnet. Throughout the experiment, the magnetic field introduced is kept constant. In this study, bare and surface functionalized magnetic iron oxide nanoparticles of three different concentrations are exposed to the magnetic field. The clustering event of those particles was observed using an optical microscope. Microscopic image of the clustering of particles was captured. The images were analysed using ImageJ software to determine the average iron oxide nanoparticles area and the number of particles from time to time. The clustering of iron oxide nanoparticles occurs rapidly in the presence of magnetic field compared to without magnetic field. As magnetic field is applied, the particles aligned towards the magnetic field and moved along the magnetic field gradient. As the particles moving, they chain with other particles forming linear aggregates in the direction of magnetic field gradient.