Effects of charge ratios of xylan-poly(allylamine hydrochloride) complexes on their adsorption onto different surfaces

The adsorption behavior of polyelectrolyte complexes (PECs) of poly(allylamine hydrochloride) (PAH) and 4-O-methylglucuronoxylan (Xyl) onto silica surface, cellulose nanofibrils (CNFs) model surfaces, and unbleached softwood kraft fibers was studied. Different charge ratios and ionic strengths of the liquid medium (q − /q +: 0.3, 0.5 and 0.8 in 1 mM NaCl, and q − /q +: 0.2, 0.3 and 0.5 in 10 mM NaCl), at pH 7.5 were considered. First, the complexes obtained were characterized by measuring the charge density, the particle size and the zeta potential. Then, the adsorption of PAH alone and PECs on silica and CNF model surfaces were studied by quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR). The QCM-D test indicated that: (a) adsorbed cationic layers of PECs were soft in 10 mM NaCl, (b) higher adsorption was observed at higher ionic strength and (c) the highest adsorption of complex and coupled water was found at a charge ratio of 0.3. The SPR results analyzed together with the corresponding QCM-D results revealed that a significant portion of the adsorbed layers corresponded to coupled water on the cationic PEC structures. Morphology and structures of the adsorbed PEC layers studied using atomic force microscopy showed that the majority of the PECs were spherical, while some bigger aggregates were also found. Finally, the retention of different PECs on an unbleached softwood pulp was determined and the maximum retention was obtained when the PEC charge ratio was 0.5 in a 10 mM NaCl solution.

Publication year: 2015
Authors: Galván MV1,Soledad Peresin M2, Mocchiutti P1, Granqvist N3, Zanuttini MA1, Tammelin T2

1 Instituto de Tecnología Celulósica, Facultad de Ingeniería Química, Universidad Nacional del Litoral
VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, Finland
BioNavis Ltd., Elopellontie 3C, FI-33470 Ylöjärvi, Finland

Published in: Cellulose, 2015, 22 [5], p. 2955-2970
DOI: doi: 10.1007/s10570-015-0706-z


adsorbed mass of polyelectrolyte complexes cellulose nanofibrils (CNF) SiO2 sensor slide


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