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http://hdl.handle.net/2289/1897
Title: | An AC Electrooptic Technique for Measuring the Flexoelectric Coefficient $\mathsf(e_1 + e_3)$ and Anchoring Energies of Nematics |
Authors: | Warrier, Sobha R. Madhusudana, N.V. |
Issue Date: | 1997 |
Publisher: | EDP Sciences |
Citation: | Journal de Physique II, 1997, Vol.7, p1789-1803 |
Abstract: | We report an AC technique to measure both the sign and magnitude of (e1 + e3) using electrooptic measurements on a hybrid aligned nematic cell. A detailed numerical analysis of the optical signal allows us to obtain the temperature dependences of (e1 + e3), the rotational viscosity coefficient $\gamma_1$ as well as the anchoring strengths at the two surfaces. Our measurements on CCH-7 show the following interesting results. a) The extrapolation length L1 at the homeotropic surface shows a small decrease as the temperature is increased to 66 $^{\circ}$C beyond which it shows a sharp increase which we interpret as arising from a softening of the chains of the aligning ODSE layer. b) The slope of the temperature dependence of the extrapolation length $L_{\rm u}$. at the homogeneous surface changes sign around 72 $^{\circ}$C. c) (e1 + e3)/S is a constant upto 72 $^{\circ}$C and decreases rapidly beyond this temperature. The last two results are attributed to an increase in the conformational freedom between the rings of CCH-7 molecules beyond that temperature. |
Description: | Restricted Access. Please click on the alternative location for the open-access full text. |
URI: | http://hdl.handle.net/2289/1897 |
ISSN: | 1155-4312 1286-4870 (Online) |
Alternative Location: | http://dx.doi.org/10.1051/jp2:1997215 |
Copyright: | (1997) Les Editions de Physique |
Appears in Collections: | Research Papers (SCM) |
Files in This Item:
File | Description | Size | Format | |
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1997 JdP V7 p1789.pdf Restricted Access | Restricted Access | 825.7 kB | Adobe PDF | View/Open Request a copy |
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