Aromatic liquid-crystalline polyesters comprising a 2,5-thiophene unit synthesized and studied by the thin-film polymerization method

Jingmei Xu, Yan Wang, Tai-Shung Chung*, Suat Hong Goh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A series of novel liquid-crystalline polymer (LCP) systems, including a heterocyclic 2,5-thiophene unit, were synthesized and studied using a modified thin-film polymerization method as part of a continuing investigation of molecular structural effects on liquid crystallinity. The monomers used in the reaction included p-acetoxybenzoic acid (ABA)/2,6-acetoxynaphtholic acid (ANA), 4,4′-biphenol (BP)/4,4′-diacetoxybiphenyl (DABP)/p-acetoxyacetanilide (AAA), and 2,5-thiophenedicarboxylic acid (TDA). Polarizing light microscopy and Fourier transform infrared spectra were used to study, in situ record the evolution of morphological change in the thin-film polymerization process, and confirm the occurrence of polymerization. Experimental results indicated that monomer structure and composition as well as temperature influence the formation of the liquid crystalline (LC) phase greatly and revealed that 2,5-thiophene structure is a viable mesogenic core unit. It is more effective than isophthalic acid (IA) in assisting in the LC formation as polymers containing TDA have a better developed LC phase and lower critical ABA content than those with IA. Stripe texture was observed in the ANA/DABP/TDA system, possibly due to the structural characteristics and matching of the monomers. The decrease of isotropic round areas in the LC phase and the annihilation between two pairs of defects with reaction time were also studied.

Original languageEnglish (US)
Pages (from-to)1509-1521
Number of pages13
JournalJournal of Materials Research
Volume18
Issue number7
DOIs
StatePublished - Jan 1 2003

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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