On the dispersion of latex particles in a nematic solution.  I. Experimental evidence and a simple model

Poulin, Philippe; Raghunathan, V. A.; Richetti, P.; Roux, Denis

doi:10.1051/jp2:1994217

Cited by 100 publications

(79 citation statements)

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“…We hope that the summary of our results stimulates further experiments which try different liquid crystals as a host fluid, manipulate the anchoring strength, investigate the effect of external fields, and attempt to disperse silica or latex spheres [36][37][38].…”

Section: Discussionmentioning

confidence: 80%

Director field configurations around a spherical particle in a nematic liquid crystal

1999

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We study the director field around a spherical particle immersed in a uniformly aligned nematic liquid crystal and assume that the molecules prefer a homeotropic orientation at the surface of the particle. Three structures are possible: a dipole, a Saturn-ring, and a surface-ring configuration, which we investigate by numerically minimizing the Frank free energy supplemented by a magneticfield and a surface term. In the dipole configuration, which is the absolutely stable structure for micron-size particles and sufficiently strong surface anchoring, a twist transition is found and analyzed. We show that a transition from the dipole to the Saturn ring configuration is induced by either decreasing the particle size or by applying a magnetic field. The effect of metastability and the occurence of hysteresis in connection with a magnetic field are discussed. The surface-ring configuration appears when the surface-anchoring strength W is reduced. It is also favored by a large saddle-splay constant K24. A comparison with recent experiments [10,13] gives a lower bound for W, i.e., W > 0.6 erg/cm 2 for the interface of water and pentylcyanobiphenyl (5CB) in the presence of the surfactant sodium dodecyl sulfate.

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Section: Discussionmentioning

confidence: 80%

Director field configurations around a spherical particle in a nematic liquid crystal

1999

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“…The factor (1 − φ) in front of the nematic mean field energy F n (Q * ) measures the local proportion of the solvent in the colloid mixture. This is the simplest possible model of nematic colloid phase ordering, essentially the same as used in [1], with minor deviations in the interpretation of nematic order-composition coupling and material constants. This interpretation, however, determines the results and predictions.…”

Section: Phase Separation Below T Nimentioning

confidence: 99%

Cellular solid behaviour of liquid crystal colloids 1. Phase separation and morphology

et al. 2001

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Abstract. We study the phase ordering colloids suspended in a thermotropic nematic liquid crystal below the clearing point Tni and the resulting aggregated structure. Small (150 nm) PMMA particles are dispersed in a classical liquid crystal matrix, 5CB or MBBA. With the help of confocal microscopy we show that small colloid particles densely aggregate on thin interfaces surrounding large volumes of clean nematic liquid, thus forming an open cellular structure, with the characteristic size of 10 − 100 µm inversely proportional to the colloid concentration. A simple theoretical model, based on the Landau mean-field treatment, is developed to describe the continuous phase separation and the mechanism of cellular structure formation.

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“…al., 2004;Zapotocky et.al., 1999) On the other hand, under a weak surface anchoring between the colloidal surface and a liquid crystal, the coupling to the orientational elasticity of the liquid crystals tends to expel the colloidal particles and the suspension shows a phase separation into an almost pure nematic phase coexisting with a colloidal rich phase. (Anderson et.al., 2001;Pouling et. al., 1994) Such phase separations induced by a nematic ordering have also been discussed in flexible polymers dispersed in a nematic liquid crystal.…”

Section: Introductionmentioning

confidence: 99%

“…(Popa-Nita et. al., 2006;Pouling et. al., 1994) In this chapter, we focus on nanoparticles dispersed in liquid crystals and discuss phase separations and phase behaviors in mixtures of a nanoparticle and a liquid crystal.…”

Section: Introductionmentioning

confidence: 99%

Phase Separations in Mixtures of a Nanoparticle and a Liquid Crystal

Matsuyama¹

2012

Smart Nanoparticles Technology

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On the dispersion of latex particles in a nematic solution. I. Experimental evidence and a simple model

Cited by 100 publications

References 1 publication

Director field configurations around a spherical particle in a nematic liquid crystal

Director field configurations around a spherical particle in a nematic liquid crystal

Cellular solid behaviour of liquid crystal colloids 1. Phase separation and morphology

Phase Separations in Mixtures of a Nanoparticle and a Liquid Crystal

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