Ferroelectric particles-liquid crystal dispersions

Reznikov, Yurii; Buchnev, Oleksandr; Glushchenko, Anatoliy; Reshetnyak, Victor; Tereshchenko, A. G.; West, John L.

doi:10.1117/12.589767

Cited by 9 publications

(9 citation statements)

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“…The particle size, measured with dynamic light scattering, was always greater than reported in recent studies [1,3,5]. Dynamic light scattering measures the hydrodynamic radius of the particles when in dilute suspension.…”

Section: (Iv) Suspensionsmentioning

confidence: 81%

“…Instead, we used ZLI2293 which is a broad range mixture for super twisted nematic displays. The choice was rationalized by the idea that if the observed shift in the Frederiks transition in Reznikov et al [1] was caused by the ferroelectric particles only, it should be liquid crystal independent. For display applications the most interesting result would be a reproducible shift in any mixture already used in display applications.…”

Section: (Iii) Liquid Crystalsmentioning

confidence: 99%

“…We chose 5CB as a well-known and well-characterized liquid crystal that was reported in recent studies [1,4] to show a shift in Frederiks transition when mixed with ferroelectric particles. The other liquid crystal used in Reznikov et al [1], ZLI4801, a super fluorinated high holding ratio mixture for active matrix displays, was not available to us. Instead, we used ZLI2293 which is a broad range mixture for super twisted nematic displays.…”

Section: (Iii) Liquid Crystalsmentioning

confidence: 99%

“…The considerable experimental and theoretical interest in suspensions of ferroelectric particles in liquid crystal hosts has arisen from reports of an enhanced dielectric anisotropy [1] and a dramatic change in the Frederiks [2] host [3]. While these improved properties are of great interest for display manufacturing, they appear to be dependent on the nematic host used and on the particle preparation and dispersion methods [4,5].…”

Section: Introductionmentioning

confidence: 99%

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The influence of suspended nanoparticles on the Frederiks threshold of the nematic host

Klein

Richardson

Greasty

et al. 2013

Phil. Trans. R. Soc. A.

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In recent years, several papers reported an enhanced dielectric anisotropy when ferroelectric particles were suspended in a liquid crystal. These results seem to be sensitive to the liquid crystal used and the preparation method of the ferroelectric particles. In this paper, we compare different preparation methods of suspended barium titanate in two different liquid crystal hosts. As a control experiment, we followed similar preparation steps with non-ferroelectric silica particles. In all cases, we found a broadening of the optical Frederiks transition but no change in the dielectric anisotropy. Raman spectroscopy has been used to investigate the loss of tetragonal structure in the barium titanate as a function of milling time and particle size. As reported in the earlier literature, barium titanate does not exhibit a welldefined tetragonal crystal structure below a certain particle size and loses its ferroelectric features. This provides a simple rationalization for the absence of any dielectric enhancement.

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Section: (Iv) Suspensionsmentioning

confidence: 81%

Section: (Iii) Liquid Crystalsmentioning

confidence: 99%

Section: (Iii) Liquid Crystalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of suspended nanoparticles on the Frederiks threshold of the nematic host

Klein

Richardson

Greasty

et al. 2013

Phil. Trans. R. Soc. A.

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“…6,[14][15][16][17][18][19][20][21][22] In addition to the size, the nanoparticle surface properties are also crucial for the manifestation of a well dispersed medium. Surface modification of NPs has been mainly been employed to achieve long-term stability of NPs in the LC medium and to smoothen director distortions around NPs, 23 thus reducing the cost of elastic energy.…”

Section: Reznikov Et Al Have Shown That a Low Concentration Of Ferromentioning

confidence: 99%

A comparison between size dependent paraelectric and ferroelectric BaTiO3 nanoparticle doped nematic and ferroelectric liquid crystals

Al-Zangana

Turner

Dierking

2017

Journal of Applied Physics

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The electro-optic and dielectric properties of barium titanate, BaTiO 3 , nanoparticle (NP) doped nematic and ferroelectric liquid crystal materials were examined with respect to different size and concentration of the NPs. Smaller size paraelectric NPs (≈80nm) are compared to larger, ferroelectric NPs (≈240nm). It is found that for concentrations larger than 0.5vol% the ferroelectric NPs exhibit an increasing effect on the electro-optic response of the nematic liquid crystal, which is demonstrated by the enhancement of the dielectric anisotropy. This could be induced by the coupling of the electrical dipole moments in the spherical NPs with the LC director field. The electro-optical properties of the SmC* phase, like tilt angle Θ, switching time and spontaneous polarisation are found to be independent of the concentration and size of the NPs. The rotational viscosity calculated from response times, polarization reversal current and dielectric properties is comparable for all three methods employed and practically independent of particle concentration and size. The relaxation frequency of the Goldstone mode is higher in the ferroelectric NPs suspensions of 2.0vol% as compared to the smaller paraelectric NPs.

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Nanoparticles in Liquid Crystals and Liquid Crystalline Nanoparticles

Stamatoiu

Mirzaei

Feng

et al. 2011

Topics in Current Chemistry

179

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Combinations of liquid crystals and materials with unique features as well as properties at the nanoscale are reviewed. Particular attention is paid to recent developments, i.e., since 2007, in areas ranging from liquid crystal-nanoparticle dispersions to nanomaterials forming liquid crystalline phases after surface modification with mesogenic or promesogenic moieties. Experimental and synthetic approaches are summarized, design strategies compared, and potential as well as existing applications discussed. Finally, a critical outlook into the future of this fascinating field of liquid crystal research is provided.

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Ferroelectric particles-liquid crystal dispersions

Cited by 9 publications

References 0 publications

The influence of suspended nanoparticles on the Frederiks threshold of the nematic host

The influence of suspended nanoparticles on the Frederiks threshold of the nematic host

A comparison between size dependent paraelectric and ferroelectric BaTiO3 nanoparticle doped nematic and ferroelectric liquid crystals

Nanoparticles in Liquid Crystals and Liquid Crystalline Nanoparticles

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