Influences Of Freely Suspended Polyelectrolyte On Aggregation Kinetics Of Magnetic Nanoparticles
Loading...
Date
2021-06-01
Authors
Azmi, Muhamad Syakir
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
This study was carried out to find the influences of freely suspended polyelectrolyte on
the aggregation kinetic of coated magnetic nanoparticles. The nanoparticles was first coated
with a polymer which is poly(sodium-4-styrenesulfonate) (PSS) and
poly (diallyldimethylammonium chloride) (PDDA). It is hypothesized that the interplay
between the depletion and electrosteric bridging effects would play a dominance role on
influencing the colloidal stability of the coated magnetic nanoparticles. Such effect of having
freely suspended polyelectrolyte in the suspension was studied at different concentration using
UV-vis-spectrophotometer and qualitatively through colour change of the suspension over
time.
Through this study, it was observed that the aggregation rate and settling velocity of
the naked IONPs suspension calculated was the highest at the values of 0.006/min and
0.0372mm/min, respectively. While PSS-IONPs and PDDA-IONPs has considerably lower
aggregation rate which was 0.0021/min and 0.0027/min, respectively.
The presence of the same charged polyelectrolyte in the suspension of coated
nanoparticles will cause higher aggregation rate which was observed highest for the suspension
of 100 ppm PSS-IONPs in 100 ppm PSS solution and 100 ppm PDDA-IONPs in 150 ppm
PDDA solution with the rate of 0.0031/min and 0.055/min, respectively. Apart from that, the
increase of concentration of polyelectrolyte in the suspension causes the sedimentation rate of
nanoparticle clusters to decrease and lowest sedimentation rate observed was for suspension of
100 ppm PSS-IONPs in 100 ppm PSS solution and 100 ppm PDDA-IONPs in 100 ppm PDDA
solution with the settling velocity of 0.00495mm/min and 0.0057mm/min, respectively. From
imaging study, at higher concentration of polyelectrolyte an observable cluster size appeared
earlier while the sedimentation rate slower.