Elastic constants, viscosity and response time in nematic liquid crystals doped with ferroelectric nanoparticles

Podoliak, Nina; Buchnev, Oleksandr; Herrington, Mark; Mavrona, Elena; Kaczmarek, Malgosia; Kanaras, Antonios G.; Stratakis, Emmanuel; Blach, Jean‐François; Henninot, J. F.; Warenghem, M.

doi:10.1039/c4ra06248e

Cited by 63 publications

(53 citation statements)

References 37 publications

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“…Based on the same analogy, the NLC molecular alignment in the vicinity of the nanoparticles will be controlled by the characteristics of the nanoparticles, such that the NLC will tend to align parallel to the surface normal of each nanoparticle rather than along the surface, as illustrated in Figure 7a. This proposed alignment is similar to that reported for colloidal systems and/or ferroelectric nanoparticles [5][6][7][8][9][10][11][12][13][14]. Here, we can compare the effects of doping with the two sizes of nanoparticles: R-812 (7 nm) and RX-50 (40 nm).…”

Section: Resultssupporting

confidence: 86%

“…More recently, ferroelectric nanoparticles have attracted significant attention with regard to controlling the responses of NLC molecules. The ferroelectric nature of these nanoparticles can greatly enhance the physical and electro-optic properties of the host LC, including its phase transition temperature, dielectric and optical anisotropy, and Fréedericksz transition [9][10][11][12][13][14]. In a ferroelectric nanoparticle-doped system, the nanoparticles behave as molecular dipoles and can therefore affect the resulting LC order.…”

Section: Introductionmentioning

confidence: 99%

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Shear-Thinning Characteristics of Nematic Liquid Crystals Doped with Nanoparticles

et al. 2016

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This work investigated changes in the physical properties of nematic liquid crystals (NLCs) upon doping with nanoparticles. Shear viscosity measurements demonstrated the shear-thinning of typical NLCs following the addition of small amounts of nanoparticles at approximately 1 wt. %. However, neither the birefringence nor the dielectric anisotropy was significantly affected at these levels of doping. The shear-thinning appears to result from the locally ordered alignment of the NLCs in the vicinity of the nanoparticles rather than from reductions in the bulk order parameters.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Shear-Thinning Characteristics of Nematic Liquid Crystals Doped with Nanoparticles

et al. 2016

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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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“…Nina Podoliak et al investigated the impact of ferroelectric nanoparticles on the basic parameters of LCs using two different nematic LCs, TL205 and 18523 [50]. The dielectric constant measurements and electro-optic study showed that the ferroelectric nanoparticle doping causes a significant increase of the dielectric anisotropy and also reduces the splay elastic constants.…”

Section: Properties Of Doped Nematic Liquid Crystalsmentioning

confidence: 99%

Dielectric and Electro-Optical Properties of Ceramic Nanoparticles Doped Liquid Crystals

Porov¹,

Chandel²,

Manohar³

2016

Transactions on Electrical and Electronic Materials

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Liquid crystals are important materials because of their applications in display technology and many other scientific applications. Different mixtures of liquid crystals and their doped samples have gained interest because a single liquid crystal compound cannot fulfill all the required parameters for the display application. The doping can be accomplished with dyes, polymers, or composite nanoparticles among other substance. The addition of nanoparticles can modify the physical properties of the host liquid crystal and enhances the performance of electro-optical devices. The present study is focused on investigations of possible changes in dielectric and electro optical properties of liquid crystals caused by doping with ceramic nanoparticles. Including smaller nanoparticles were found to be better candidates for use in suppressing the unwanted ion effects in liquid crystal displays.

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Elastic constants, viscosity and response time in nematic liquid crystals doped with ferroelectric nanoparticles

Cited by 63 publications

References 37 publications

Shear-Thinning Characteristics of Nematic Liquid Crystals Doped with Nanoparticles

Shear-Thinning Characteristics of Nematic Liquid Crystals Doped with Nanoparticles

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

Dielectric and Electro-Optical Properties of Ceramic Nanoparticles Doped Liquid Crystals

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