Synthesis and characterisation of side chain liquid crystal copolymers containing sulfonic acid groups

A Martinez-Felipe, Z.B. Lu, P.A. Henderson, Stephen J. Picken, Ben Norder, Corrie T. Imrie, Amparo Ribes-Greus

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

A series of novel side chain liquid crystal copolymers, the poly[10-(4-methoxy-4'-oxy-azobenzene) decyl methacrylate]-co-poly[2-acrylamido-2-methyl-1-propanesulfonic acid]s (10-MeOAzB/AMPS-x/y) have been synthesised by free radical copolymerisation. The mol fraction of the sulfonic acid-based group, AMPS, has been varied over a broad range of composition in the copolymers, and these have been characterised using differential scanning calorimetry (DSC), polarised light microscopy (PLM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The liquid crystal homopolymer and copolymers containing up to 0.54 mol fraction AMPS-based units, all exhibit a smectic A phase, while at higher mol fraction AMPS-based groups, liquid crystallinity is extinguished and the copolymers are amorphous. The local packing arrangements within the smectic A phase varies with composition attributed, in part, to phase separation between acid rich domains and liquid crystal regions. The dependence of the transitional properties on copolymer composition may be interpreted in terms of the packing efficiency of the mesogenic side chains and hydrogen bonding between the sulfonic acid groups, as a consequence of increasing the concentration of acid-based groups. (c) 2012 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)2604-2612
Number of pages9
JournalPolymer
Volume53
Issue number13
Early online date23 Feb 2012
DOIs
Publication statusPublished - 7 Jun 2012

Keywords

  • side chain liquid crystal copolymers
  • sulfonic acid
  • hydrogen bonding
  • methanol fuel-cell
  • polymer electrolytes
  • thermal-properties
  • transitional properties
  • ion-transport
  • backbone flexibility
  • nonmesogenic units
  • spacer length
  • ionomers
  • polystyrene

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