Reinvestigation of the block copolymer modulated lamellar structure

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We report extended crystallographic studies on shear-aligned block copolymer systems within the metastable modulated lamellae (ML) state. With studies limited to the "classical" orientations parallel and perpendicular to shear plane, the apparent modulated state would likely have been assigned simple lamellar. Surprisingly, upon rotating the sample to intermediate angles additional scattering reflections appear, which reveal the apparent ML phase much beyond what was expected. The modulated structure is a slightly distorted fcc structure. With the sample sheared at relatively low temperature, presumably below the stable gyroid phase, we find a very well resolved ML texture corresponding to a simple twin structure of the distorted fcc structure. When shear-aligned within the hexagonal cylinder phase, and quenced to the gyroid phase or slightly below, we find ML alignment into a two-dimensional powder texture.

Original languageEnglish
JournalMacromolecules
Volume42
Issue number5
Pages (from-to)1685–1690
Number of pages6
ISSN0024-9297
DOIs
Publication statusPublished - 2009

ID: 14335699