Converse flexoelectric effect in bent-core nematic liquid crystals

Pramoda Kumar; Y. G. Marinov; H. P. Hinov; Uma S. Hiremath; C. V. Yelamaggad; K. S. Krishnamurthy; A. G. Petrov

doi:10.1021/jp903241z

Converse flexoelectric effect in bent-core nematic liquid crystals

Pramoda Kumar, Y. G. Marinov, H. P. Hinov, Uma S. Hiremath, C. V. Yelamaggad, K. S. Krishnamurthy, A. G. Petrov

Research output: Contribution to journal › Article › peer-review

49 Scopus citations

Abstract

We report on the converse flexoelectric effect in two bent-core nematic liquid crystals with opposite dielectric anisotropies. The results are based on electro-optic investigations of inplane field-driven distortions in homeotropic samples (the Helfrich method). They are interpreted by an extension of the Helfrich theory that takes into account the higher order distortions. The bend flexocoefficient for both the compounds is of the usual order of magnitude as in calamitics, unlike in a previously investigated bent-core nematic for which giant values of the bend flexocoefficient are reported. In order to resolve this discrepancy, we propose a molecular model with nonpolar clusters showing quadrupolar flexoelectricity. The study also includes measurements on surface polarization instabilities in the dielectrically positive material; the splay flexocoefficient thereby deduced is also of the conventional order.

Original language	English
Pages (from-to)	9168-9174
Number of pages	7
Journal	Journal of Physical Chemistry B
Volume	113
Issue number	27
DOIs	https://doi.org/10.1021/jp903241z
State	Published - 9 Jul 2009
Externally published	Yes

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Surfaces, Coatings and Films
Materials Chemistry

Access to Document

10.1021/jp903241z

Cite this

@article{e1a53aed0ff0460fad347a8c1586642b,

title = "Converse flexoelectric effect in bent-core nematic liquid crystals",

abstract = "We report on the converse flexoelectric effect in two bent-core nematic liquid crystals with opposite dielectric anisotropies. The results are based on electro-optic investigations of inplane field-driven distortions in homeotropic samples (the Helfrich method). They are interpreted by an extension of the Helfrich theory that takes into account the higher order distortions. The bend flexocoefficient for both the compounds is of the usual order of magnitude as in calamitics, unlike in a previously investigated bent-core nematic for which giant values of the bend flexocoefficient are reported. In order to resolve this discrepancy, we propose a molecular model with nonpolar clusters showing quadrupolar flexoelectricity. The study also includes measurements on surface polarization instabilities in the dielectrically positive material; the splay flexocoefficient thereby deduced is also of the conventional order.",

author = "Pramoda Kumar and Marinov, {Y. G.} and Hinov, {H. P.} and Hiremath, {Uma S.} and Yelamaggad, {C. V.} and Krishnamurthy, {K. S.} and Petrov, {A. G.}",

year = "2009",

month = jul,

day = "9",

doi = "10.1021/jp903241z",

language = "English",

volume = "113",

pages = "9168--9174",

journal = "Journal of Physical Chemistry B",

issn = "1520-6106",

publisher = "American Chemical Society",

number = "27",

}

TY - JOUR

T1 - Converse flexoelectric effect in bent-core nematic liquid crystals

AU - Kumar, Pramoda

AU - Marinov, Y. G.

AU - Hinov, H. P.

AU - Hiremath, Uma S.

AU - Yelamaggad, C. V.

AU - Krishnamurthy, K. S.

AU - Petrov, A. G.

PY - 2009/7/9

Y1 - 2009/7/9

N2 - We report on the converse flexoelectric effect in two bent-core nematic liquid crystals with opposite dielectric anisotropies. The results are based on electro-optic investigations of inplane field-driven distortions in homeotropic samples (the Helfrich method). They are interpreted by an extension of the Helfrich theory that takes into account the higher order distortions. The bend flexocoefficient for both the compounds is of the usual order of magnitude as in calamitics, unlike in a previously investigated bent-core nematic for which giant values of the bend flexocoefficient are reported. In order to resolve this discrepancy, we propose a molecular model with nonpolar clusters showing quadrupolar flexoelectricity. The study also includes measurements on surface polarization instabilities in the dielectrically positive material; the splay flexocoefficient thereby deduced is also of the conventional order.

AB - We report on the converse flexoelectric effect in two bent-core nematic liquid crystals with opposite dielectric anisotropies. The results are based on electro-optic investigations of inplane field-driven distortions in homeotropic samples (the Helfrich method). They are interpreted by an extension of the Helfrich theory that takes into account the higher order distortions. The bend flexocoefficient for both the compounds is of the usual order of magnitude as in calamitics, unlike in a previously investigated bent-core nematic for which giant values of the bend flexocoefficient are reported. In order to resolve this discrepancy, we propose a molecular model with nonpolar clusters showing quadrupolar flexoelectricity. The study also includes measurements on surface polarization instabilities in the dielectrically positive material; the splay flexocoefficient thereby deduced is also of the conventional order.

UR - http://www.scopus.com/inward/record.url?scp=67650074406&partnerID=8YFLogxK

U2 - 10.1021/jp903241z

DO - 10.1021/jp903241z

M3 - Article

AN - SCOPUS:67650074406

SN - 1520-6106

VL - 113

SP - 9168

EP - 9174

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

IS - 27

ER -

Converse flexoelectric effect in bent-core nematic liquid crystals

Abstract

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this