Effects of polydispersity on the order-disorder transition of diblock copolymer melts
Department of Mathematics, University of Reading, RG6 6AX, Reading, Whiteknights, UK
Published online: 30 October 2008
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.
PACS: 82.35.Jk Copolymers, phase transitions, structure – / 61.46.-w Structure of nanoscale materials –
© Springer, 2008