Adsorption of polyelectrolytes with hydrophobic parts

Abstract

Polyelectrolytes offer numerous possibilities for modification of particles, planar inorganic or polymer surfaces, and control of colloidal stability. Significant enhancement of flocculation properties can be achieved through introduction of hydrophobic functionalities into polyelectrolyte backbone that increases surface activity and allow formation of polyelectrolyte aggregates. Here the flocculation performance of a high molecular weight cationic polyelectrolyte with hydrophobic functionalities, PMBQ (poly(methacryloyloxyethyl dimethylbenzyl-ammonium chloride)) was investigated in stable kaolin dispersions using turbidity measurements for efficiency estimation. Polyelectrolyte aggregates of PMBQ obtained at high ionic strength have shown superior flocculation properties in comparison with non-aggregated PMBQ. Remarkable difference in water and salt solutions was found in mono- and multilayer formation using polyanion medium molecular weight polystyrenesulfonate (PSS) and PMBQ. Streaming potential measurements, in-situ SPR and AFM were used to follow and quantify layer build up and charge reversal at the solid/liquid interface at the molecular level. SPR measurements, allowing in-situ control of polyelectrolyte adsorption process, have revealed that the layers thickness depended strongly on ionic strength. However, AFM has shown that the layers obtained had very high roughness. © Springer-Verlag Berlin Heidelberg 2006.