Smectic liquid crystals modified by tail and core fluorination

Robert J. Twieg; K. M. Betterton; Richard C. DiPietro; D. Gravert; Cattien V. Nguyen; H. T. Nguyen; A. Babeau; C. Destrade

doi:10.1117/12.44683

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1 June 1991 Smectic liquid crystals modified by tail and core fluorination

Robert J. Twieg; K. M. Betterton; Richard C. DiPietro; D. Gravert; Cattien V. Nguyen; H. T. Nguyen; A. Babeau; C. Destrade

Author Affiliations +

Proceedings Volume 1455, Liquid-Crystal Devices and Materials; (1991) https://doi.org/10.1117/12.44683
Event: Electronic Imaging '91, 1991, San Jose, CA, United States

Abstract

The systematic substitution of fluorine for hydrogen in mesogenic materials has proved to be of great value for the modification of a wide range of physical properties. This is especially true in the case of ferroelectric liquid crystals in which the fluorine has been strategically introduced into the aromatic core (k), at or near the chiral center (Z) or in the achiral tail (n) in the generic liquid crystal (with X equals O, S and Z equals Me, halogen): H/F(CF2)n(CH2)mOC6H(4 - k)FkCOXPhOCOC*HZR. In this system the fluorine can be introduced in any of these three specific locations, or any combinations thereof, with the intent of enhancing performance such as broadening of the ferroelectric Sc* phase temperature range, enhancement of the magnitude of spontaneous polarization Ps and a variety of more subtle yet important modifications such as viscosity and dielectric and optical anisotropy. The ramifications of the incorporation of fluorine on these physical properties are discussed with a variety of examples.

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Robert J. Twieg, K. M. Betterton, Richard C. DiPietro, D. Gravert, Cattien V. Nguyen, H. T. Nguyen, A. Babeau, and C. Destrade "Smectic liquid crystals modified by tail and core fluorination", Proc. SPIE 1455, Liquid-Crystal Devices and Materials, (1 June 1991); https://doi.org/10.1117/12.44683

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