Dielectric Permittivity and Viscoelastic Measurements οf Two Tricomponent Mixtures Consisting οf Laterally Fluorinated Terphenyl Derivatives

• Authors: S. Basak , P. Dasgupta , B. Das , M. Das , R. Dabrowski
• Languages of publication: EN

Abstracts

EN

Two tricomponent room temperature nematic eutectic mixtures ABC and ABD with laterally fluorinated constituents A and B were prepared as base mixtures for vertically aligned mode LCD's. The physical properties of these mixtures viz. birefringence, dielectric anisotropy, bend elastic constant, relaxation time and rotational viscosities were determined in order to compare with the optimum values required to achieve the target specifications of VA mode materials. The dielectric anisotropy, Δ ε, and optical birefringence, Δ n, of these mixtures were found to be in the range of (-1.3 to -1.4) and (0.13 and 0.14), respectively, at around 20°C. The figure of merit for the ABD mixture has been found to be higher than that of ABC mixture throughout the entire temperature range. The pretilt angle effect in the physical parameters has also been studied. At T=20°C, the response time decreases to 25% and 35% for mixture ABC for 2° and 5° pretilt respectively in comparison to zero pretilt. On the other hand, at the same temperature for the ABD mixture these values are reduced by 16% and 35%, respectively.

Keywords

EN

61.30.-v; 78.20.Fm; 87.19.rd; 87.19.rf; 83.60.Bc

Discipline

• 78.20.Fm: Birefringence
• 87.19.rd: Elastic properties
• 83.60.Bc: Linear viscoelasticity
• 87.19.rf: Dielectric properties
• 61.30.-v: Liquid crystals(for phase transitions in liquid crystals, see 64.70.M-; for liquid crystals as dielectric materials, see 77.84.Nh; for liquid crystals as optical materials, see 42.70.Df; for liquid crystal devices, see 42.79.Kr)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2013
• Volume: 123
• Issue: 4
• Pages: 714-719

Dates

published

2013-04

received

2012-04-14

(unknown)

2012-11-05

Contributors

author

S. Basak

• Department of Physics, Siliguri Institute of Technology, Siliguri, Darjeeling - 734 ,009, India

author

P. Dasgupta

• Department of Physics, Siliguri Institute of Technology, Siliguri, Darjeeling - 734 ,009, India

author

B. Das

• Department of Physics, Siliguri Institute of Technology, Siliguri, Darjeeling - 734 ,009, India

author

M. Das

• Department of Physics, University of North Bengal, Siliguri, Darjeeling - 734 ,013, India

author

R. Dabrowski

• Department of Advanced Technologies and Chemistry, Military University of Technology 00-908 Warsaw, Poland

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Identifiers

DOI

10.12693/APhysPolA.123.714