Observation of temporal change of the hydrodynamic layer thickness of adsorbed polyelectrolytes on spherical particles by single-particle-tracking method

Abstract

The temporal behavior of adsorbed polymers is important in the analysis of colloid–polymer systems. The single-particle-tracking method provides a reliable approach to acquiring information on the adsorbed polymer layer on a spherical particle. Imaging, tracking, and analysis of the Brownian motion of a single colloidal particle with/without adsorbed polymers provided the trajectory of the Brownian motion and the layer thickness of adsorbed polymers. The temporal decrease in the thickness of an adsorbed polyelectrolyte layer was monitored within 2 h. A polyelectrolyte with a high charge density formed a thick layer on the particle surface and the layer thickness rapidly decreased. A polyelectrolyte with a low charge density formed a thinner layer, and its thickness decreased slightly. The transient adsorption behavior in a system undergoing flocculation can be used for the analysis of adsorption and flocculation in colloid–polymer systems.