ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 8, pp. 1424!1428. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + B.B. Troitskii, L.V. Khokhlova, V.N. Denisova, M.A. Novikova, D.A. Smirnov, M.A. Baten’kin, 2007, published in Zhurnal
Prikladnoi Khimii, 2007, Vol. 80, No. 8, pp. 1385!1390.
AND POLYMERIC MATERIALS
Influence of the Synthesis Conditions of Emulsion
Poly(Methyl Methacrylate) on the Surface Structure
of the Specimens
B. B. Troitskii, L. V. Khokhlova, V. N. Denisova, M. A. Novikova,
D. A. Smirnov, and M. A. Baten’kin
Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Nizhni Novgorod, Russia
Received February 22, 2007
Abstract-The surface structure of poly(methyl methacrylate) specimens prepared by emulsifier-free
emulsion polymerization of methyl methacrylate was examined in relation to the synthesis conditions
(pH of the medium, initiator concentration, and addition of organosilicon compounds).
A considerable attention is received today by poly-
meric periodic nanosize structures, the so-called colloid
crystals . Research efforts in this field are aimed
to prepare monodisperse colloid particles capable of
strictly ordered stacking. A source of such particles
can be found, e.g., in products of emulsion polymeri-
zation, such as polystyrene (PS) [1, 2], copolymers
of styrene with methacrylic acid or glycidyl meth-
acrylate [3, 4], poly(methyl methacrylate) (PMMA)
[3, 5], poly-tert-butyl methacrylate , copolymers of
methyl methacrylate (MMA) with styrene , and
copolymers of 2-hydroxypropyl methacrylate with
4-vinylpyridine, obtained in the presence of organo-
silicon compounds .
The above-mentioned materials  have been
synthesized by emulsifier-free emulsion polymerization
yielding stable polymer dispersions with particles of
identical size in water. Dispersions of this kind have
been used for preparing photonic crystals . It
should be noted that the most extensively studied was
the emulsifier-free polymerization of hydrophobic sty-
rene monomer in water in the presence of a hydrophilic
initiator, potassium (sodium, ammonium) persulfate .
The major task to be accomplished now is to find
the best conditions for preparing strictly ordered col-
loid crystals. This makes it necessary to examine
the crystal structure in relation to the preparation
technique of colloid particles.
In this study, we examined the particle-size distri-
bution of PMMA latexes as influenced by the condi-
tions of emulsifier-free emulsion polymerization of
MMA (pH of the medium, initiator concentration,
and additions of alkoxysilanes). Also, we analyzed
the suitability of these dispersions for preparation
of colloid crystals.
The PMMA specimens were prepared by emulsi-
fier-free emulsion polymerizations of MMA in acid,
neutral, and alkaline media (pH 3, 5, 7, 9, 10) with
0.07, 0.08, 0.35, and 1.00% potassium persulfate
as initiator. The pH value was adjusted with
0.1 M HCl or 0.1 M NaOH, introduced into tvice-dis-
tilled water; it was measured on a Potential laboratory
potentiometric titrometer. We did not introduce buffer
additions to avoid further complication of the system.
During polymerization, the pH of the system tends to
decrease owing to decomposition of the initiator [1,
12]. In selected experiments, a prescribed amount (1,
3, 5, 7, 10, and 20 wt%) of tetraethoxysilane (TEOS)
was added to the reaction mixture.
Water (10 ml) with a known pH of the medium
was poured into a 50-ml three-necked flask equipped
with a reflux condenser, stirrer, and capillary for
argon supply, and heated to 80oC. When the desired
temperature was achieved, 1.0 ml of the monomer,
MMA, was added, and the mixture was stirred for
5 min. Next, 1.0 ml of a solution of the initiator, po-
tassium persulfate (0.07, 0.08, 0.35, and 1.00% of
the weight of the mixture) was added (in selected