Picture of two heads

Open Access research that challenges the mind...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including those from the School of Psychological Sciences & Health - but also papers by researchers based within the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

On the change in helix handedness at transitions between the SmC* and phases in chiral smectic liquid crystals

Lagerwall, Jan P.F. and Giesseimann, Frank and Osipov, Mikhail (2006) On the change in helix handedness at transitions between the SmC* and phases in chiral smectic liquid crystals. Liquid Crystals, 33 (6). pp. 625-633. ISSN 0267-8292

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

Using a discrete model for the synclinic SmC* and the anticlinic phases we give a theoretical explanation for the fact that the helix twisting sense reverses at a transition between these phases (direct transition or via the so-called chiral smectic C 'subphases') and we derive an explicit expression for the helical pitch in the phase. As the theory shows and as we also demonstrate experimentally, the reversal is of a different nature from helix inversions within a single phase, where the inversion is always coupled to a pitch divergence. At a clinicity change the common behaviour is instead pitch-shortening on approaching the phase transition and the associated helix twisting sense reversal. The phenomenon may be put to use in smart mixing in order to control the helix pitch, either for achieving long pitch for surface-stabilized ferroelectric and antiferroelectric liquid crystal displays; or a very short pitch, in the case of devices utilizing the deformed helix mode.