| Numéro |
J. Phys. I France
Volume 5, Numéro 3, March 1995
|
|
|---|---|---|
| Page(s) | 365 - 377 | |
| DOI | https://doi.org/10.1051/jp1:1995131 | |
J. Phys. I France 5 (1995) 365-377
Fluctuation Theory of Random Copolymers
Andrey V. Dobrynin1 and Igor Ya. Erukhimovich21 Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627-0011, U.S.A.
2 Department of Physics, Moscow State University, Moscow 117234, Russia
(Received 28 April 1994, revised 30 August 1994, accepted 23 November 1994)
Abstract
We investigate the behavior of symmetric AB random copolymer melt near the point of microphase
separation in the framework of a one-loop (Hartree-Fock) approximation, that exactly solves the
problem. We have shown that composition fluctuations result to complete elimination of the
microphase separation predicted in the framework a mean-field approximation [1-5]. Using
variational techniques the temperature dependence of the density-density correlation function and
its length scales are calculated. The diagonal in the replica space correlation function is stable
with respect to the off-diagonal perturbation (glass-like order parameter). We discuss the general
relation between microphase separation in random copolymers and spinodal decomposition in a mixture
of A and B unconnected monomer units below their critical demixing point.
© Les Editions de Physique 1995