Study of phase transitions in liquid crystalline side group polymers via photon transmission method


Ozbek H. , YILDIZ S. , PEKCAN O., HEPUZER Y., YAGCI Y. , GALLI G.

MATERIALS CHEMISTRY AND PHYSICS, vol.78, no.2, pp.318-322, 2003 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 78 Issue: 2
  • Publication Date: 2003
  • Doi Number: 10.1016/s0254-0584(02)00300-0
  • Title of Journal : MATERIALS CHEMISTRY AND PHYSICS
  • Page Numbers: pp.318-322

Abstract

Photon transmission measurements were applied to study the phase transitions of an acrylate monomer, 3-(4-cyanobiphenyl-4'-oxy)propyl acrylate (LC3), its homopolymer (PLC3) and its graft copolymer (GLC3) with polytetrahydrofuran grafts. In PLC3 drastic decrease in the transmitted light intensity was attributed to a first-order isotropic-nematic phase transition. The phase transitions were also confirmed by DSC and polarizing microscopy. No phase transition was observed in GLC3. This method was not able to detect the isotropic-nematic phase transition in GLC3, probably because of the small size of the phase separated domains in this graft copolymer. The isotropic-nematic transition of GLC3 was identified by polarizing microscopy only by the appearance of a weak diffuse birefringence on cooling. (C) 2002 Elsevier Science B.V. All rights reserved.