Electroconvection characterization of guest-host nematic liquid crystals for dynamic scattering mode applications

ABSTRACT The threshold voltage for electro-hydrodynamic convection (EHC) in nematic liquid crystals in the low-frequency convective regime is examined. The addition of dopant species is known to strongly effect the frequency response of this regime. In this work, we investigate the effect of adding optically anisotropic species on the low-frequency threshold, and, demonstrate that certain dichroic dyes have a marked effect. We have measured electrical transport properties of suitably doped liquid crystal mixtures in order to make a comparison with theoretical predictions based upon linear stability considerations. Our results show satisfactory agreement with these predictions. Our findings indicate future directions for new applications of dynamic scattering mode technologies with more accessible operating parameters previously known. Graphical abstract

[1]  J. Gleeson,et al.  Enhancement in electro-optic properties of dynamic scattering systems through addition of dichroic dyes , 2018, AIP Advances.

[2]  P. Salamon,et al.  Electrically induced patterns in nematics and how to avoid them , 2016 .

[3]  Martin Schadt,et al.  LIQUID CRYSTAL MATERIALS AND LIQUID CRYSTAL DISPLAYS , 1997 .

[4]  M. Treiber,et al.  Travelling Waves in Electroconvection of the Nematic Phase 5: A Test of the Weak Electrolyte Model , 1997, patt-sol/9701007.

[5]  A. Buka,et al.  On The Optical Characterization of Convection Patterns in Homeotropically Aligned Nematics , 1994 .

[6]  L. Kramer,et al.  On electrically driven pattern-forming instabilities in planar nematics , 1988 .

[7]  T. Uchida,et al.  Dichroic Dyes for Guest-Host Liquid-Crystal Cells , 1986 .

[8]  B. Bahadur.  A Brief Review of Histoty, Present Status, Developments and Market Overview of Liquid Crystal Displays , 1983 .

[9]  T. Uchida,et al.  Dichroic Azo Dyes for Guest-Host Liquid-Crystal Cell , 1982 .

[10]  S. Kai,et al.  Successive Transitions in Electrohydrodynamic Instabilities of Nematics , 1978 .

[11]  M. I. Barnik,et al.  Experimental verification of the theory of electrohydrodynamic instability in nematic liquid crystals , 1975 .

[12]  P. G. de Gennes,et al.  Hydrodynamic instabilities of nematic liquid crystals under A. C. electric fields , 1971 .

[13]  W. Helfrich,et al.  Erratum: Conduction‐Induced Alignment of Nematic Liquid Crystals: Basic Model and Stability Considerations , 1969 .

[14]  A. Buka,et al.  CONVECTIVE PATTERNS IN LIQUID CRYSTALS DRIVEN BY ELECTRIC FIELD An overview of the onset behaviour , 2005 .

[15]  Lorenz Kramer,et al.  Convection instabilities in nematic liquid crystals , 1995 .

[16]  W. Helfrich.  Electric Alignment of Liquid Crystal , 1973 .