Enhanced enantiotropic B2 phase by mixing homologous chlorine-substituted molecules

Abstract

The phase diagram of a binary system was presented by mixing two components: an achiral five-ring bent-core molecule with monotropic B₂ phase and a homologous chlorine-substituted bent-core molecule with enantiotropic nematic phase and monotropic X phase. Depending on the mixing concentrations, the enantiotropic B₂ phase, B₁ phase and nematic phase were induced in the mixed phase region. The mesophases occurring in this system were characterised by optical textures, X-ray diffraction and electro-optical measurements. The results indicated that the formation of the enantiotropic B₂ phase occurred even when the mixing concentration reached 60 mol%. The spontaneous polarisation and switching time of the B₂ phase are also discussed.

Keywords:

• binary system
• bent-core molecule
• spontaneous polarisation
• switching time

Acknowledgements

This work was supported by the National Science Council contract number NSC97-2221-E-011-005. The authors wish to thank Professor K.T. Liu of the Department of Chemistry of NTU Taiwan for his guidance in the synthesis process.