Eur. Phys. J. E (2008) 27: 323-333
https://doi.org/10.1140/epje/i2008-10383-6

Regular Article

Effects of polydispersity on the order-disorder transition of diblock copolymer melts

Department of Mathematics, University of Reading, RG6 6AX, Reading, Whiteknights, UK

^* e-mail: t.m.beardsley@reading.ac.uk
^** e-mail: m.w.matsen@reading.ac.uk

Received: 6 August 2008
Published online: 30 October 2008

Abstract

The effect of polydispersity on an AB diblock copolymer melt is investigated using lattice-based Monte Carlo simulations. We consider melts of symmetric composition, where the B blocks are monodisperse and the A blocks are polydisperse with a Schultz-Zimm distribution. In agreement with experiment and self-consistent field theory (SCFT), we find that polydispersity causes a significant increase in domain size. It also induces a transition from flat to curved interfaces, with the polydisperse blocks residing on the inside of the interfacial curvature. Most importantly, the simulations show a relatively small shift in the order-disorder transition (ODT) in agreement with experiment, whereas SCFT incorrectly predicts a sizable shift towards higher temperatures.