Deposition Kinetics of Iron Oxide Nanoparticles on a Poly(diallyldimethylammonium Chloride)-Coated Silica Surface: Influences on the Formation of a Softer Particle-Polyelectrolyte Layer

Abstract

Particle-polyelectrolyte layers with an open structure were constructed by using cationic poly(diallyldimethylammonium chloride) (PDDA) as a binder to promote the attachment of iron oxide nanoparticles (IONPs) onto silica colloids. The deposition kinetics of IONPs onto PDDA-coated silica surfaces were monitored by a quartz crystal microbalance with dissipation (QCM-D). Here, our experiments provide clear evidence of the direct influences of deposition kinetics on the structural properties of the formed PDDA/IONP layers. At low IONP deposition rates, ‘softer’ particle-polyelectrolyte layers were formed with a great amount of IONPs attached to the outer compartment of these layers. This unique feature of the polymer-particle system can be further modulated by varying the ionic strength of the background medium, containing both PDDA and IONPs. As the ionic strength of the solution is increased, the PDDA/IONP assembled layers become more flexible, leading to a larger amount of deposited IONPs and reducing the...