Sign reversal in the dielectric anisotropy as functions of temperature and frequency in the nematic phase of a bent-core mesogen

被引：16

作者：

Jang, Yun ^{[1
]}

Panov, Vitaly P. ^{[1
]}

Keith, C. ^{[2
]}

Tschierske, C. ^{[2
]}

Vij, J. K. ^{[1
]}

机构：

[1] Univ Dublin Trinity Coll, Dept Elect & Elect Engn, Dublin 2, Ireland

[2] Univ Halle Wittenberg, Inst Organ Chem, D-06120 Halle, Germany

来源：

APPLIED PHYSICS LETTERS | 2010年 / 97卷 / 15期

基金：

欧盟第七框架计划;

关键词：

LIQUID-CRYSTALS; PERMITTIVITY;

D O I：

10.1063/1.3498674

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

The sign reversal in the dielectric anisotropy (epsilon(parallel to)' -epsilon(perpendicular to)') from positive to negative is observed for 4-cyanoresorcinol bisbenzoate system with temperature and frequency in the nematic phase of a bent-core system as the temperature is reduced. This cross-over in dielectric anisotropy is such that at temperatures much below the cross-over temperature, the negative anisotropy is found to be independent of frequency. The experimental observation is supported by results from optical transmittance spectroscopy. This observation is suggested to arise from the following two sources: the presence of cybotactic clusters found by x-ray scattering in the same compound in its nematic phase and conformers that may change the bent core angle at a certain temperature as observed by nuclear magnetic resonance in a similar compound. (c) 2010 American Institute of Physics. [doi:10.1063/1.3498674]

引用

页数：3

共 12 条

[11] Structure studies of the nematic phase formed by bent-core molecules [J].

Vaupotic, N. ;

Szydlowska, J. ;

Salamonczyk, M. ;

Kovarova, A. ;

Svoboda, J. ;

Osipov, M. ;

Pociecha, D. ;

Gorecka, E. .

PHYSICAL REVIEW E, 2009, 80 (03)

[12] Nematic biaxiality in a bent-core material [J].

Yoon, Hyung Guen ;

Kang, Shin-Woong ;

Dong, Ronald Y. ;

Marini, Alberto ;

Suresh, Kattera A. ;

Srinivasarao, Mohan ;

Kumar, Satyendra .

PHYSICAL REVIEW E, 2010, 81 (05)

← 1 2 →