Role of Polyelectrolyte Persistence Length in the Binding of Oppositely Charged Micelles, Dendrimers, and Protein to Chitosan and Poly(dimethyldiallyammonium chloride)

Abstract

The effect of polyelectrolyte chain flexibility on adsorption to oppositely charged colloidal particles and its parametrization by persistence length have been investigated by comparison of PDADMAC and chitosan, polycations of equal linear charge density but of respectively low and high bare persistence lengths, relatively. Their relative affinity to (i) nonionic/anionic mixed micelles, (ii) carboxyl-terminated dendrimers, and (iii) bovine serum albumin (BSA) was studied by turbidimetric titrations. Potentiometric titrations and dynamic light scattering experiments as well as molecular modeling with SPARTAN were used to characterize and model these systems. The experimental and modeling results lead to the conclusion that while chain stiffness does influence the binding of polyelectrolytes to oppositely charged colloids, the persistence length is not necessarily an appropriate measure of chain flexibility on short length scales.