Comparative study of the mesomorphic properties of several laterally fluorinated liquid crystalline materials

Abstract

Laterally fluorinated bi- and ter-phenyl compounds exhibiting negative dielectric anisotropy are widely used in multicomponent mixtures for application in vertically aligned (VA) mode liquid crystal displays (LCDs). This work reports the mesomorphic and viscoelastic properties of several laterally fluorinated compounds with the aim to identify suitable compounds as components of mixtures for VA mode LCDs. The position of the fluoro substituent in the rigid core and the variation of the terminal alkyl/alkoxy chain have been found to have a pronounced effect on the physical properties of these compounds. Moreover, the viscoelastic coefficient, figure of merit and orientational order parameter values have also been reported. The physical properties of the series of LC compounds investigated here have emerged to be promising for display applications.

Keywords:

• laterally fluorinated liquid crystals
• negative dielectric anisotropy
• birefringence
• rotational viscosity
• figure of merit

Acknowledgements

One of the authors (P. Dasgupta) is thankful to DST for the award of a Senior Research Fellowship.

Additional information

Funding

Financial support from DST, New Delhi (Project No: SR/S2/CMP-29/2007) to B. Das is gratefully acknowledged.