title: Surface-induced rearrangement of polyelectrolyte complexes: influence of complex composition on adsorbed layer properties.
abstract: 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 SiO(2) 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 SiO(2) 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 properties with adsorption time were very different for the two types of PECs. The PEC-A complexes showed a coalescence into larger block of complexes on the SiO(2) surface, but this was not detected with the PEC-B. The size determinations of the complexes in solution showed that they were very stable over time, and it was therefore concluded that the coalescence of the complexes was induced by the interaction between the complexes and the surface. The results also indicated that polyelectrolytes can migrate between the different complexes adsorbed to the surface. The results also give indications that the preparation of PEC-B leads to the formation of two different types of polyelectrolyte complexes differing in the amount of polymer in the complexes; i.e., two populations of complexes were formed with similar sizes but with totally different adsorption structures at the solid-liquid interface.
authors.affiliation: Department of Pulp and Paper Technology, Faculty of Forestry, Karadeniz Technical University, 61080 Trabzon, Turkey.
authors.forename: Sedat
authors.initials: S
authors.lastname: Ondaral
authors.forename: Caroline
authors.initials: C
authors.lastname: Ankerfors
authors.forename: Lars
authors.initials: L
authors.lastname: Odberg
authors.forename: Lars
authors.initials: L
authors.lastname: Wågberg
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D018625:Microscopy, Atomic Force; D010316:Particle Size; D011073:Polyamines / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques; D012822:Silicon Dioxide / Q000737:chemistry; D012996:Solutions; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D011073:Polyamines; D012996:Solutions; C063994:polyallylamine; C006903:carbopol 940; D012822:Silicon Dioxide