Non-equilibrium phase behavior of diblock copolymer melts and binary blends in the intermediate segregation regime

Paul M. Lipic, Frank S. Bates, Mark W. Matsen

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

The phase behavior of intermediately segregated (XN = 45) poly(ethylene)-poly(ethylethylene) (PE-PEE) diblock copolymers and PE-PEE binary blends are characterized using transmission electron microscopy and small-angle X-ray scattering. Surprisingly, the preparation-dependent, nonequilibrium phase behavior can be overwhelming even at this degree of segregation. A pure diblock with a poly(ethylene) volume fraction of fPE = 0.46 exhibited coexisting lamellae and perforated layers when prepared using a precipitation technique, but contained only the lamellar morphology when solvent cast. This preparation dependence was more dramatic in binary diblock copolymer blends with average compositions of 〈fPE〉 = 0.44, 0.46, and 0.48. Precipitated blends exhibited a microphase separated structure that was disordered and bicontinuous; however, solvent cast samples exhibited either a cylindrical, coexisting cylindrical and lamellar, or lamellar morphology. This nonequilibrium behavior is attributed to the high degree of segregation and the proximity to the cylinder/lamellae phase boundary.

Original languageEnglish (US)
Pages (from-to)2229-2238
Number of pages10
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume37
Issue number16
DOIs
StatePublished - Aug 15 1999

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