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

Beardsley, T. M. and Matsen, M. W. (2008) Effects of polydispersity on the order-disorder transition of diblock copolymer melts. European Physical Journal E, 27 (3). pp. 323-333. ISSN 1292-8941 doi: 10.1140/epje/i2008-10383-6

Abstract/Summary

The effect of polydispersity on an AB diblock copolymer melt is investigated using latticebased 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.