Phase separation and coalescence, annihilation of liquid crystal textures during polymerization of main-chain liquid crystalline polyesters

Si Xue Cheng, Tai Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Using a novel thin film polymerization technique, we have observed the phase separation, coalescence, and annihilation of liquid crystal textures during polymerization of wholly aromatic main-chain liquid crystalline polymer poly(p-oxybenzoate/2,6-oxynaphthoate) (P(OBA/ONA)). The polycondensation reaction was conducted and observed in situ on the heating stage of a polarizing microscope. After the melting of monomers, the reaction system started from a homogeneous phase and then changed into a heterogeneous one. The following morphological changes during the entire reaction were observed: generation of anisotropic phase, coalescence of liquid crystal domains, formation of schlieren texture, annihilation of disclinations, and formation of stripe texture. We found all the liquid crystal domains formed in the isotropic melt during the early stage of our polymerization reactions had the disclination strength of +1. The number of defects decreased with increasing reaction time through coalescence and annihilation. At the early stage of polymerization, the dominant factor affecting annihilation rate was the viscosity characteristics at elevated temperatures.

Original languageEnglish (US)
Pages (from-to)4923-4932
Number of pages10
JournalJournal of Physical Chemistry B
Volume103
Issue number23
StatePublished - Jun 10 1999
Externally publishedYes

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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