AND POLYMERIC MATERIALS
Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 5, pp. 756−759.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © M.N. Nikolaeva, T.D. Anan’eva, A.A. Martynenkov, E.P. Astapenko, Yu.M. Boiko, 2013, published in Zhurnal Prikladnoi Khimii,
2013, Vol. 86, No. 5, pp. 809−812.
Inﬂ uence of Chemical Structure and Chain Length
on Conducting Properties of Dielectric Polymers
in Metal/Polymer/Metal Structures
M. N. Nikolaeva, T. D. Anan’eva, A. A. Martynenkov,
E. P. Astapenko, and Yu. M. Boiko
Institute of High-Molecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia
Received October 19, 2012
Abstract—The inﬂ uence of weight-average molecular mass M
on the maximal width of a conducting layer
of polysterene, polymethylmethacrylate, and polyamidine ﬁ lms was investigated. It was shown that h
increases in proportion to M
for all investigated polymers. It points to the fact that the h
value is deﬁ ned by
the macromolecular coil size.
Studies of conducting properties of thin ﬁ lms of
polymers, which possess dielectric properties in bulk,
attract attention of researchers for several decades [1–12].
This interest is caused by the fact that knowledge of the
whole combination of factors capable to affect conducting
properties of polymer ﬁ lms of various chemical structures
will allow creating electronic devices working even on
the basis of polymeric dielectrics.
Not only conjugated interfaced doped polymers, but
also non-conjugate polymers [1–12] are conducting poly-
mers, if they are used on metal electrodes in the form of
thin ﬁ lms with the width not exceeding certain critical
value . Usually this critical width is of the value from
hundreds nanometers up to several micrometers [10–12],
and such ﬁ lms possess a metal-type conductivity [3–8].
Various maximul widths of a conducting layer h
various polymers , most likely, show that conditions
of charge penetration into a depth of a polymer ﬁ lm de-
pend on chemical structure of the polymers. It is known
that the presence of electronic states in a polymer on a
metal Fermi level is necessary for passing conductiv-
ity electrons from a metal in a polymer ﬁ lm [13, 14]. A
supramolecular structure of polymer compounds also
essentially affects h
[10, 12, 15]. So, for example, the
change of a solvent for the polysaccharide arabinogalac-
tan from ordinary water to deuterated water reduces the
value from 8 to 3 μm for ﬁ lms obtained from these
solutions [10, 12]. In this case changes in h
correlate with size changes of macromolecular associates
in corresponding arabinogalactan solutions . At the
same time the solvent used for obtaining the polymer ﬁ lms
is not the unique factor inﬂ uencing the supermolecular
structure of polymer compounds. In particular, a change
of polymer molecular weights can be such a factor.
The aim of this work was to study the inﬂ uence of
molecular weight and also of solvents type on conducting
properties of thin ﬁ lms of polymeric dielectrics.
Atactic polydisperse polysterene (PS) with average
molecular weights from 38 000 up to 490 000 g mol
and polymethylmethacrylate (PMMA) with average
molecular weightы from 47 000 up to 3 700 000 g mol
were synthesized by the radical polymerization method.
The polymerization was carried out in soldered ampoules
in argon atmosphere in solution (solvent toluene) using
azoisobutyrate dinitrile as an initiator. Polymethylmeth-
acrylate with M
= 3 700 000 g·mol
was obtained by
bulk polymerization in conditions described in . Poly-