Please use this identifier to cite or link to this item:
http://hdl.handle.net/2289/2914
Title: | An experimental investigation of electromechanical coupling in cholesteric liquid crystals |
Authors: | Madhusudana, N.V. Pratibha, R. |
Issue Date: | 1989 |
Publisher: | Taylor & Francis |
Citation: | Liquid Crystals, 1989, Vol.5, 1827 - 1840 |
Abstract: | Cholesteric liquid crystals which have a helical arrangement of oriented chiral molecules are expected to show novel cross couplings between fluxes and forces. The most convincing demonstration of these couplings is through a dynamical effect on the structure. Though Lehmann found a rotation of the structure under a temperature gradient in 1900, there has been no subsequent experiment confirming the same. We argue that it is very difficult to obtain a sufficiently weak anchoring of the director at the solid-cholesteric interface which is a necessary condition for the occurrence of Lehmann rotation. In order to achieve a practically zero anchoring energy at the surface, we have devised a simple technique of floating essentially flat cholesteric drops in the isotropic phase. Using this configuration we study the electromechanical coupling which produces a rotation of the structure under the action of a DC electric field. Using measurements on samples with different values of the pitch the relevant electromechanical coefficient of the materials investigated is found to satisfy the relation vE = -0·6 × 10-12(q/m-1)J m-2, where q is the wavevector of the helix, whose sign is positive (negative) for a right (left) handed structure, confirming that vE is hydrodynamic in origin. |
Description: | Restricted Access. |
URI: | http://hdl.handle.net/2289/2914 |
ISSN: | 0267-8292 1366-5855 (online) |
Alternative Location: | http://dx.doi.org/10.1080/02678298908045691 |
Copyright: | 1989 Taylor & Francis |
Appears in Collections: | Research Papers (SCM) |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
1989 LC V5 p1827.pdf Restricted Access | Restricted Access | 875.71 kB | Adobe PDF | View/Open Request a copy |
Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.