Numéro |
J. Phys. I France
Volume 5, Numéro 6, June 1995
|
|
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Page(s) | 657 - 669 | |
DOI | https://doi.org/10.1051/jp1:1995158 |
J. Phys. I France 5 (1995) 657-669
Glass Transition Versus Microphase Separation: a Phenomenological Replica-Field Theory for AB Copolymer Systems
Andrey V. DobryninDepartment of Physics and Astronomy, University of Rochester, Rochester, New York 146270011, U.S.A.
(Received 3 August 1994, revised 29 November 1994, accepted 16 February 1995)
Abstract
We present a phenomenological replica-field theory for symmetric AB copolymer systems with the
A-block near its glass transition point. Using a variational principle based on the second Legendre
transformation we prove that the interaction between composition fluctuations, due to the loss
mobility of the A monomers, results in the elimination of microphase separation. Instead of a
microphase separation there is a third-order phase transition between the homogeneous state and a
glass-like state with broken replica symmetry of the two-replica density-density correlation
function. We show that near the point of the glass transition two-replica correlation function
is proportional to the square of the one-replica correlation function
, where
is a matrix describing the
metric properties of the replica space. The phase diagram for this class of copolymer systems is
calculated.
© Les Editions de Physique 1995