ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 6, pp. 830−835. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © E.A. Mezina, I.M. Lipatova, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 6, pp. 821−827.
AND POLYMERIC MATERIALS
Formation of the Dispersed Phase in Mixed Solutions
of Chitosan and Magnesium Sulfate
E. A. Mezina and I. M. Lipatova
Krestov Institute of Solution Chemistry, Russian Academy of Sciences,
ul. Akademicheskaya 1, Ivanovo, 153045 Russia
Received April 25, 2014
Abstract—Speciﬁ c features of formation and the composition and characteristics of dispersed phase particles in
mixed dilute solutions of chitosan and magnesium sulfate, containing no surfactants, were studied. The component
molar ratio, ν
, is the factor exerting the strongest inﬂ uence on the formation rate and characteristics of
chitosan sulfate particles. With an increase in the fraction of sulfate ions in the initial solution, the particle size
decreases and their ζ-potential increases. The ν
molar ratio in chitosan sulfate particles only slightly
depends on the composition of the initial mixed solution and varies within 0.40–0.44.
Chitosan is a biologically active natural polysaccha-
ride ﬁ nding increasing use in various branches of medi-
cine and pharmacology owing to a set of unique properties
(biocompatibility, mucoadhesion, biodegradability, low
toxicity, etc.). In particular, aqueous dispersions formed
by meso- and nanosized chitosan particles, which can
be used as drug carriers, are of much interest [1–3]. One
of simple procedures for preparing such dispersions is
precipitation due to electrostatic interaction of proton-
ated amino groups of chitosan with polycharged anions,
in particular, with tripolyphosphate and sulfate [3–5].
Data on speciﬁ c medical use of chitosan particles with
biologically active substances immobilized on them are
reported in numerous papers [5–7]. In the papers cited, the
particle characteristics (size, morphology, surface charge)
were determined after completion of the formation of the
dispersed phase in the system; in some studies, the disper-
sion was allowed to stand for a long time for this purpose.
In addition, it should be noted that the dispersions were
stabilized in these studies with nonionic surfactants which
did not affect the ζ-potential of the particles [1–5].
It has been shown that aqueous dispersions formed by
meso- and nanosized chitosan particles can be used for
discrete dressing of ﬁ brous materials . The particles
immobilized on ﬁ bers form an anchor layer of a sort,
which can efﬁ ciently adsorb functional agents imparting
special properties to the ﬁ brous material.
It is known that particles undergo rapid aggregation
without surface-active stabilizers [1, 4]. Efﬁ cient immo-
bilization of particles on ﬁ brous or any other substrates is
possible only when stabilization of particles with surfac-
tants is excluded, with the surface being dressed playing
the stabilizing role itself. Furthermore, in contrast to the
above-cited papers in which the sodium salt was used as
a source of sulfate ions, in this study we used magnesium
sulfate. This choice was governed by the fact that with
magnesium sulfate, according to the experimental data,
impregnation of ﬁ brous materials with the dispersions
obtained yields more reproducible results regarding
the particle immobilization on ﬁ bers. For solving some
process problems and predicting the dressing results, it
is necessary to understand the inﬂ uence of various fac-
tors on the formation rate and characteristics of chitosan
particles in aqueous dispersions.
This study was aimed at revealing how the composi-
tion of surfactant-free mixed aqueous solutions of chi-
tosan and magnesium sulfate affects the formation rate,
composition, and characteristics of particles of chitosan