Method for Determination of Rotational Viscosity in Nematic Liquid Crystals

Abstract

A simple method is proposed for the determination of the rotational viscosity of nematic liquid crystals. Theoretical expressions for the rotational viscosity from transient displacement current in nematic liquid crystals are derived. It is demonstrated that the values of the rotational viscosity measured with this method are in excellent agreement with the Merck data.

Transient Response Characteristics of Polymer Stabilized Bend Alignment State of Nematic Liquid Crystal in Pi-Cell

“…For the measurement of the rotational viscosity of NLC, we used the transient displacement current method proposed by Imai et al 14) At first, we must confirm whether the transient displacement current method can be applicable for the case when the polymer stabilization term is introduced. Now we consider a NLC cell having a homogeneous alignment with the pretilt angle 0 at both boundaries.…”

Synthesis and Physicochemical Properties of Novel Liquid Crystal Compounds with Negative Dielectric Anisotropy with a Tetrahydropyran Ring: Part 2

“…Melting point and transition temperature were individually measured using a Mettler FP82HT Hot-stage (with FP90 central processor) on which a Nikon ECLIPSE LV100 POL polarization microscope was mounted. The values ε [6] and n [7] of the newly synthesized LC compounds were extrapolated from measured Downloaded by [Universidad de Sevilla] at 04:05 05 November 2014 [8] and rotational viscosity were also measured through methods described in previous reports [9].…”

Measurement of viscosities from the transient current of nematic liquid crystals with negative dielectric anisotropy

“…By means of our method, we can accurately derive the complete set of the Leslie viscosity coefficients (α 1 , α 2 , α 3 and α 4 + α 5 ) of NLCs with Δε b 0 in display device configurations. In addition, the experimental setup for the measurement of the transient currents [17,18] is the simplest among the conventional methods to measure the viscosities of NLCs with Δε b 0 mentioned above.…”