Director orientation of nematic side-chain liquid crystalline polymers under shear flow: Comparison of a flow-aligning and a non-flow-aligning polysiloxane

Hartmut Siebert, Isabel Quijada-Garrido, Jan Vermant, Laurence Noirez, Wesley Roth Burghardt, Claudia Schmidt*

*Corresponding author for this work

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The flow behavior and phase structure of two side-chain liquid-crystalline polysiloxanes with the same mesogens but different spacers of either four (PSi4) or six (PSi6) methylene groups are studied in the nematic phase by 2H NMR, polarization microscopy, and scattering of light, neutrons, and X-rays. PSi4 is flow-aligning, forming a monodomain with the director close to the flow direction, whereas PSi6 is non-flow-aligning showing a polydomain structure with a preferred director orientation corresponding to the log-rolling state. The flow behavior of PSi6 is related to the presence of strong smectic clusters. The director tilt in the smectic clusters of both polymers is reported.

Original languageEnglish (US)
Pages (from-to)2161-2172
Number of pages12
JournalMacromolecular Chemistry and Physics
Volume208
Issue number19-20
DOIs
StatePublished - Oct 24 2007

Keywords

  • Liquid-crystalline polymers (LCP)
  • NMR
  • Phase behavior
  • Scattering
  • Shear

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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