Clustering of polyelectrolyte coated magnetic nanoparticles under repetitive cycle of magnetization
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Date
2018-06
Authors
Muhammad Azwar Hafify Zulkifli
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Abstract
The sample of naked iron oxide nanoparticles (IONPs) was prepared and been
functionalized by using poly (diallyldimethylammonium chloride) (PDDA) electrolyte as
a coating agent in order to improve the colloidal stability of the IONPs in the suspension.
The presence of PDDA as an adlayer adsorbed on IONPs introduced electrosteric
stabilization towards particles in suspension, thus suppressed the van der Waals attraction
and magnetic dipole-dipole interaction force between particles reducing particles
aggregation. Characterization of naked IONPs and functionalized IONPs been conducted
by using dynamic light scattering (DLS) for particles size and zeta potential measurement.
The characterization to ensure the successful coating of IONPs with PDDA
macromolecules. The IONPs samples are prepared into 3 different concentration (50, 100
and 500 ppm) to conduct the study on effect of repetitive exposure of IONPs sample
towards magnetic field. The major focuses would be the effect on the cluster size formed
and colloidal stability of particles suspension after been subjected to repetitive
magnetization. The magnetization cycle of IONPs samples was started from 1 cycle
followed by 3 and 5 magnetization cycles. For cluster size formed, as going up the
magnetization cycle there was not much different can be seen from the particles size
measurement by DLS for all concentrations. The same thing goes to study on colloidal
stability of particles been conducted through kinetic study by UV-Vis spectrophotometer,
measuring the absorbance of IONPs sample. The decay rate for normalized absorbance
was almost the same for all magnetization cycles and concentrations that proving the
repetitive magnetization has relatively insignificant effect towards particles stability in
suspension.