1070-4272/05/7806-1008 + 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 6, 2005, pp. 1008!1012. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005,
Original Russian Text Copyright + 2005 by Men’shikova, Evseeva, Shabsel’s, Balanina, Sirotkin, Ivanchev.
AND POLYMERIC MATERIALS
Synthesis of Monodisperse Polystyrene Particles in the Presence
of Sodium Dodecyl Sulfate and Carboxyl-containing Initiator
A. Yu. Men’shikova, T. G. Evseeva, B. M. Shabsel’s, I. V. Balanina,
A. K. Sirotkin, and S. S. Ivanchev
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Research Institute of Grippe, Russian Academy of Medical Sciences, St. Petersburg, Russia
St. Petersburg Branch, Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences,
St. Petersburg, Russia
Received February 11, 2005
Abstract-Emulsion polymerization of styrene in the presence of an anionic surfactant, sodium dodecyl
sulfate, in a concentration close to the critical micellization concentration, was studied, as influenced by
the pH of the initial reaction mixture and the content of the carboxyl-containing azoinitiator.
Monodisperse polystyrene (PS) particles have long
been used as calibration standard for electron micro-
scopy. These particles are widely used for electron
microscopic determination of the concentration of
various components of natural water and, in particular,
viruses, whose size is determined with the aid of
an internal latex reference. To estimate quantitatively
the virus population and the quality of drinking water,
503150 nm latex monodispersions with similar poly-
meric structure are required. These references can
also be used to estimate the retentivity of various
antiviral filters and nutrient media and sera in pro-
duction of vaccines and biologicals. Modification of
the surface of latex particles with functional groups
(e.g. carboxy groups) allows covalent binding of bio-
ligands to the surface. The modified particles can be
used to simulate virus particles not only in size but
also in bioselective surface markers.
Submicrometer monodisperse microspheres of PS
and poly(methyl methacrylate) (PMMA), containing
surface carboxy groups, were prepared by emulsifier-
free emulsion polymerization initiated by 4,4`-azo-
bis(4-cyanoisovaleric acid) (CIVA) . The stabil-
ity of these particles against aggregation is provided
by the surface charge produced in ionization of the ter-
minal carboxy groups of the polymeric chains .
The degree of ionization of the initiator and polymer-
ization products and, hence, the surface concentration
of carboxy groups and the particle size depend on
the pH of the reaction mixture. These particles can
be used in biotechnology, since their carboxylated
surface interacts with small biologically active com-
pounds. The constancy of the polymeric structure
of the particle surface makes it possible to provide
the optimal conditions of immumochemical reactions
with the surface change controlled by varying the pH
of the reaction mixture.
To prepare 100-nm particles of this type, an emul-
sifier should be introduced into the reaction mixture
to stabilize additionally the developed interface .
However, particles formed on the surface can migrate
into the dispersion medium to promote there nuclea-
tion of new particles, thus broadening the particle
size distribution of the latex.
To prepare 503150-nm latex dispersions and to
determine the factors affecting the dispersity of latex
particles and the surface concentration of carboxy
groups, we studied emulsion polymerization of sty-
rene as influenced by the concentrations of emulsifier,
sodium dodecyl sulfate (SDS), initiator (CIVA), and
protons in the reaction mixture.
Styrene was distilled under a reduced pressure.
The procedures for treating CIVA are described in .
Sodium dodecyl sulfate (Serva) and standard solutions
of HCl and NaOH were used as received. The poly-
merization was performed in double-distilled water.
The procedure for preparing latexes has been described
elsewhere . The styrene to aqueous phase weight ra-