Use of xylan on polyelectrolyte complexes: model surfaces study on the effect of charge ratios on structural and adsorption behavior

MARÍA V. GALVÁN; MARÍA S. PERESÍN; PAULINA MOCCHIUTTI; TEKLA TAMMELIN; MIGUEL A. ZANUTTINI

Nice

Congreso; 3rd EPNOE International Polysaccharide Conference; 2013

EPNOE (European Polysaccharide Network of excellence), ACS

Structural changes and adsorption behaviour of polyelectrolyte complexes (PECs) formed by poly(allylamine hydrochloride) (PAH) and beechwood O-acetyl-4-O-methylglucuronoxylan (Xyl), as a function of charge ratios were studied. PECs were formed by adding anionic Xyl on cationic PAH solution at different charge ratios (q-/q+) (0.3; 0.5 and 0.8), and ionic strengths (1 and 10 mM NaCl), while maintaining a constant pH value of 7.5. A decrease in the charge of the complexes was observed to increase the size of the complexes as indicated by zeta potential, size and charge densities values. Additionally, morphology and structures of the adsorbed PECs layers were investigated using Atomic Force Microscopy. PECs were found to be spherical with the presence of few complex aggregates. Adsorption behaviour of PECs on model surfaces of nanocellulose obtained from unbleached softwood kraft-liner was studied by using Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) and Surface Plasmon Resonance (SPR). Highest adsorption of PECs was found at charge ratio 0.5 and 10 mM NaCl by QCM-D, while SPR revealed that a significant portion of this adsorbed layer was due to the presence of coupled water on the PECs structure.