Surface-Induced Rearrangement of Polyelectrolyte Complexes : Influence of Complex Composition on Adsorbed Layer Properties

The adsorption characteristics of two different types of polyelectrolyte complexes (PECs), prepared by mixing poly(allylamine hydrochloride) and poly(acrylic acid) in a confined impinging jet (CIJ) mixer, have been investigated with the aid of stagnation point adsorption reflectometry (SPAR), a quartz crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM) using SiO2 surfaces. The two sets of PEC were prepared by combining high molecular mass PAH/PAA (PEC-A) and low molecular mass PAH/PAA (PEC-B). The PEC-A showed a higher adsorption to the SiO2 surfaces than the PEC-B. The adsorption of the PEC-A also showed a larger change in the dissipation (ΔD), according to the QCM-D measurements, suggesting that the adsorbed layer of these complexes had a relatively lower viscosity and a lower shear modulus. Complementary investigations of the adsorbed layer using AFM imaging showed that the adsorbed layer of PEC-A was significantly different from that of PEC-B and that the changes in proper...