Thermal processing of diblock copolymer melts mimics metallurgy

Kyungtae Kim, Morgan W. Schulze, Akash Arora, Ronald M. Lewis, Marc A. Hillmyer, Kevin D. Dorfman, Frank S. Bates

Research output: Contribution to journalArticle

79 Scopus citations

Abstract

Small-angle x-ray scattering experiments conducted with compositionally asymmetric low molar mass poly(isoprene)-b-poly(lactide) diblock copolymers reveal an extraordinary thermal history dependence. The development of distinct periodic crystalline or aperiodic quasicrystalline states depends on how specimens are cooled from the disordered state to temperatures below the order-disorder transition temperature. Whereas direct cooling leads to the formation of documented morphologies, rapidly quenched samples that are then heated from low temperature form the hexagonal C14 and cubic C15 Laves phases commonly found in metal alloys. Self-consistent mean-field theory calculations show that these, and other associated Frank-Kasper phases, have nearly degenerate free energies, suggesting that processing history drives the material into long-lived metastable states defined by self-assembled particles with discrete populations of volumes and polyhedral shapes.

Original languageEnglish (US)
Pages (from-to)520-523
Number of pages4
JournalScience
Volume356
Issue number6337
DOIs
StatePublished - May 5 2017

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