Bent-Core Liquid Crystals: Their Mysterious and Attractive World

Takezoe, Hideo; Takanishi, Yoichi

doi:10.1143/jjap.45.597

Cited by 793 publications

(543 citation statements)

References 213 publications

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“…Especially, the location of the CoH is unknown before the motion of any tracking point (TP) is analyzed. Boomerang particles are also an interesting model system for active microswimmers [37], the electro-optical properties of DNA molecules [39][40][41][42] and the liquid crystal ordering [43].Our experimental and theoretical studies show that the diffusion of the boomerangs is rather different from that of spheres and ellipsoids. (1) The mean displacements (MD) for fixed initial angle are biased towards the CoH, and the mean square displacements (MSDs) exhibit a crossover from short to long time diffusion with different diffusion coefficients.…”

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confidence: 90%

Brownian Motion of Boomerang Colloidal Particles

et al. 2013

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Brownian Motion of Boomerang Colloidal ParticlesWe investigate the Brownian motion of boomerang colloidal particles confined between two glass plates. Our experimental observations show that the mean displacements are biased towards the center of hydrodynamic stress (CoH), and that the mean-square displacements exhibit a crossover from short time faster to long time slower diffusion with the short-time diffusion coefficients dependent on the points used for tracking. A model based on Langevin theory elucidates that these behaviors are ascribed to a superposition of two diffusive modes: the ellipsoidal motion of the CoH and the rotational motion of the tracking point with respect to the CoH.Brownian motion as a general phenomenon of the diffusion processes has inspired extensive research [1][2][3][4][5][6][7][8][9][10][11][12] due to both its interesting physics and practical applications such as in microrheology [13][14][15][16], selfpropelled microswimmers [17] and particle and molecular separation [18][19][20]. Inspired by the diverse geometric shapes of biological macromolecules, Brenner and others have extended the hydrodynamic theory of Brownian motion to particles with irregular shapes [21][22][23][24][25][26]. A set of hydrodynamic centers are introduced, which include the center of hydrodynamic stress (CoH) where the coupling diffusion matrix becomes zero, the center of reaction where the coupling resistance matrix becomes symmetric and the center of diffusion where the coupling diffusion matrix becomes symmetric [22,24,27]. For screw-like or skewed particles, the translational and rotational motions are intrinsically coupled, therefore, the CoH does not exist and the centers of diffusion and reaction differ from each other. By contrast, for non-skewed particles, there always exists a unique point at which these three hydrodynamic centers coincide.Thus far, experimental studies of Brownian motion have been focused primarily on spherical particles; it was only recently that the Brownian motion of lowsymmetry particles was explored in experiments [5,[28][29][30][31][32][33][34]. Particle shapes are critical to various applications such as self-propelled microswimmers and particle/molecular separations [17,35]. By engineering particle shapes, microswimmers may be tailored to perform circular, spinning-top or other types of motion [35][36][37]. Understanding the hydrodynamics of chiral particles may lead to new avenues towards separation of particle or molecular enantiomers [38].In this letter we study the Brownian motion of boomerang-shaped colloidal particles under quasi twodimensional confinements. The boomerang particles with C 2v mirror symmetry represent an attractive system for studying the Brownian motion of low symmetry particles because their CoM and CoH do not coincide and both lie outside the body. Especially, the location of the CoH is unknown before the motion of any tracking point (TP) is analyzed. Boomerang particles are also an interesting model system for active microswimmers [37], the elec...

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confidence: 90%

Brownian Motion of Boomerang Colloidal Particles

et al. 2013

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“…T he study of bent-core liquid crystals revealed many interesting and unique phenomena, including the interplay among chirality, molecular bend and director tilt 1 leading to peculiar layered structures labelled originally as B s (s ¼ 1-7) [2][3][4] . Remarkably, the B7 and B4 structures are helical in the micrometre 5 or nanometre 6 ranges, respectively.…”

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Helical nanofilaments of bent-core liquid crystals with a second twist

et al. 2014

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The B4 phase of bent-core liquid crystals has been shown to be an assembly of twisted layers stacked to form helical nanofilaments. Interestingly, some of them have structural colours that cannot be explained by the nanofilaments alone. Here cryogenic-transmission electron microscopy observations on 40-120 nm films of four bent-core liquid crystal materials show that the filaments are present even in contact with a carbon substrate with only minor deformation, thus representing bulk properties. We find that the subsequent arrays of nanofilaments are not parallel to each other, but rotate by an angle of 35-40°with respect to each other. This doubly twisted structure can explain the structural colour. Being principally different from the packing of molecules in the twist grain boundary and blue phases, the double-twist structure of helical nanofilaments expands the rich word of nanostructured organic materials.

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“…The bent-core mesogens are the first ferroelectric and antiferroelectric liquid crystals realized without introducing chirality [4]. Molecule spontaneous polarization will be incurred because of the bent molecule polarity accumulation occurred in smectic phase layer [5].…”

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confidence: 99%

Smectic liquid crystals comprising triazole banana shaped achiral molecules: Synthesis and characterization

Zongying

Liuya

2017

Molecular Crystals and Liquid Crystals

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A series of novel liquid crystals containing [1,2,3]-triazole ring were synthesized via "click chemistry. " Their mesomorphic properties and photoelectric properties were investigated and the results indicated that most of compounds exhibited SmA over a wide temperature range (about 50°C). The threshold voltage and the response time of the mixture, T4 and LC 50100 were shorten 0.43 V and 71.5 ms with respect to those of LC 50100 respectively.

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Bent-Core Liquid Crystals: Their Mysterious and Attractive World

Cited by 793 publications

References 213 publications

Brownian Motion of Boomerang Colloidal Particles

Brownian Motion of Boomerang Colloidal Particles

Helical nanofilaments of bent-core liquid crystals with a second twist

Smectic liquid crystals comprising triazole banana shaped achiral molecules: Synthesis and characterization

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