Abstract
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.
Original language | English |
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Pages (from-to) | 2955-2970 |
Journal | Cellulose |
Volume | 22 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2015 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Ionic strength
- Cellulose nanofibrils
- Unbleached cellulosic fibers
- QCM-D
- SPR