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Science 3 November 1995:
Vol. 270. no. 5237, pp. 783 - 786
DOI: 10.1126/science.270.5237.783
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Reports

On the Origins of Spontaneous Polarization in Tilted Smectic Liquid Crystals

Demetri J. Photinos and Edward T. Samulski (1)

The rapid electrooptic response of ferroelectric liquid crystals-stratified (smectic) melts exhibiting spontaneous electric polarization-makes them candidates for the next generation of electrooptic shutters and liquid crystal displays. The model advanced here suggests that polarity is indigenous to tilted smectics and that spontaneous polarization derives from the packing constraints mesogens experience, a tilt-dependent correlation of molecular conformation with orientation. First-rank orientational order parameters (C) are nonzero with a tilt- (temperature-) dependent magnitude, and under certain packing conditions, the sign of C varies with tilt. These results have a direct bearing on experimental observations because most ferroelectric liquid crystals exhibit a tilt-dependent spontaneous polarization and some show an inversion of the sign of the polarization.


D. J. Photinos, Department of Physics, University of Patras, Patras 26100, Greece.
E. T. Samulski, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290.
(1) To whom correspondence should be addressed.

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Science. ISSN 0036-8075 (print), 1095-9203 (online)