Dynamics of a thermoreversible transition between cylindrical and hexagonally perforated lamellar mesophases

Chiajen Lai, Yueh Lin Loo, Richard Alan Register, Douglas H. Adamson

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

A polystyrene-poly(ethylene-alt-propylene) diblock copolymer, S/EP 7/13, exhibits a thermoreversible mesophase transition between low-temperature hexagonally perforated lamellae (HPL) and high-temperature hexagonally packed cylinders (C). The transformation process is accompanied by a 6% change in the principal spacing, yet oriented specimens retain their macroscopic orientation through the transition. The C → HPL transformation proceeds on a time scale of tens of minutes, at a rate which initially increases rapidly with undercooling relative to the order-order transition temperature. At deep undercoolings, the transformation rate slows due to a reduction in molecular mobility. By contrast, the HPL → C transformation occurs nearly 2 orders of magnitude more rapidly, a difference which is suggested to reflect the nature of the dominant fluctuation modes for the two structures.

Original languageEnglish (US)
Pages (from-to)7098-7104
Number of pages7
JournalMacromolecules
Volume38
Issue number16
DOIs
StatePublished - Aug 9 2005

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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