Plenary Lecture. The blue phases. A review of experiments

Crooker, P. P.

doi:10.1080/02678298908026383

Cited by 193 publications

(68 citation statements)

References 121 publications

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“…[1] Among different frustrated mesophases, the blue phases, which were discovered first, [2] are usually stable within a temperature range of a few degrees and are mostly characterized by isotropic structures. [3] An example of anisotropic frustrated phases is represented by the so-called twist grain boundary (TGB) phases, [1] predicted by Renn and Lubensky [4] and discovered experimentally in 1989.…”

Section: Introductionmentioning

confidence: 99%

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete²H and¹³C NMR Study

et al. 2008

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A liquid crystal (HZL 7/*) containing an (S)-2-methylbutyl-(S)-lactate unit in the chiral chain, is investigated by means of (2)H and (13)C NMR spectroscopy in order to obtain information on its orientational order, its molecular structure and the effect of external magnetic fields on the supramolecular structure of its phases. This mesogen presents very peculiar mesomorphic properties and exhibits frustrated TGBA* and TGBC* phases in a wide temperature range up to 60 degrees C, as well as an additional phase transition from TGBC(1)* to TGBC(2)*. (2)H NMR measurements show, for the first time, a peculiar magnetic field effect in unwinding the supramolecular structure of both the TGBA* and TGBC* phases. This effect is particularly evident at higher magnetic fields, while different behaviour is observed at lower magnetic fields. This indicates that the supramolecular structure is very sensitive to magnetic fields of the order of 1 Tesla. Moreover, the analysis of the (2)H and (13)C NMR spectra of HZL 7/* allow us to obtain several structural properties, such as the tilt angle of the TGBC* phases and the local orientational order parameters referred to the phenyl and biphenyl fragments. This is the first structural characterization of the frustrated phases of these complexes by means of NMR.

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Section: Introductionmentioning

confidence: 99%

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete²H and¹³C NMR Study

et al. 2008

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“…This type of nanoparticle ordering, somewhat different from the previously described approaches, is also being explored for other purposes, in particular with the aim to expand the temperature range of liquid crystal blue phases. These are exotic liquid crystal phases characterized by a cubic lattice of disclinations that may form in case of very strong chiral interactions [218]. The phase is in fact isotropic due to the cubic symmetry of the lattice, but birefringence can be induced by applying an electric field, and the display industry currently has a keen interest in the possibilities of exploiting this effect in displays that could be very fast and require no alignment control [219].…”

Section: Colloidal Particles Organized By Liquid Crystals and Liquid mentioning

confidence: 99%

A new era for liquid crystal research: Applications of liquid crystals in soft matter nano-, bio- and microtechnology

Lagerwall

Scalia

2012

Current Applied Physics

646

351

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a b s t r a c tLiquid crystals constitute a fascinating class of soft condensed matter characterized by the counterintuitive combination of fluidity and long-range order. Today they are best known for their exceptionally successful application in flat panel displays, but they actually exhibit a plethora of unique and attractive properties that offer tremendous potential for fundamental science as well as innovative applications well beyond the realm of displays. Today this full breadth of the liquid crystalline state of matter is becoming increasingly recognized and numerous new and exciting lines of research are being opened up. We review this exciting development, focusing primarily on the physics aspects of the new research thrusts, in which liquid crystals e thermotropic as well as lyotropic e often meet other types of soft matter, such as polymers and colloidal nano-or microparticle dispersions. Because the field is of large interest also for researchers without a liquid crystal background we begin with a concise introduction to the liquid crystalline state of matter and the key concepts of the research field. We then discuss a selection of promising new directions, starting with liquid crystals for organic electronics, followed by nanotemplating and nanoparticle organization using liquid crystals, liquid crystal colloids (where the liquid crystal can constitute either the continuous phase or the disperse phase, as droplets or shells) and their potential in e.g. photonics and metamaterials, liquid crystal-functionalized polymer fibers, liquid crystal elastomer actuators, ending with a brief overview of activities focusing on liquid crystals in biology, food science and pharmacology.

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“…Blue phases (BPs) are known as frustrated intermediate phases appearing between cholesteric phase and isotropic phase [1,[7][8][9][10]. BPs can be formed in a narrow temperature range.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Rheology and Fracture of Disclination Network in Cholesteric Blue Phase III

Fujii

Sasaki

Orihara

2018

Fluids

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Nonlinear rheological properties of chiral crystal cholesteryl oleyl carbonate (COC) in blue phase III (BPIII) were investigated under different shear deformations: large amplitude oscillatory shear, step shear deformation, and continuous shear flow. Rheology of the liquid crystal is significantly affected by structural rearrangement of defects under shear flow. One of the examples on the defect-mediated rheology is the blue phase rheology. Blue phase is characterized by three dimensional network structure of the disclination lines. It has been numerically studied that the rheological behavior of the blue phase is dominated by destruction and creation of the disclination networks. In this study, we find that the nonlinear viscoelasticity of BPIII is characterized by the fracture of the disclination networks. Depending on the degree of the fracture, the nonlinear viscoelasticity is divided into two regimes; the weak nonlinear regime where the disclination network locally fractures but still shows elastic response, and the strong nonlinear regime where the shear deformation breaks up the networks, which results in a loss of the elasticity. Continuous shear deformation reveals that a series of the fracture process delays with shear rate. The shear rate dependence suggests that force balance between the elastic force acting on the disclination lines and the viscous force determines the fracture behavior.

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Plenary Lecture. The blue phases. A review of experiments

Cited by 193 publications

References 121 publications

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete²H and¹³C NMR Study

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete²H and¹³C NMR Study

A new era for liquid crystal research: Applications of liquid crystals in soft matter nano-, bio- and microtechnology

Nonlinear Rheology and Fracture of Disclination Network in Cholesteric Blue Phase III

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Plenary Lecture. The blue phases. A review of experiments

Cited by 193 publications

References 121 publications

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete2H and13C NMR Study

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete2H and13C NMR Study

A new era for liquid crystal research: Applications of liquid crystals in soft matter nano-, bio- and microtechnology

Nonlinear Rheology and Fracture of Disclination Network in Cholesteric Blue Phase III

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Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete²H and¹³C NMR Study

Twist Grain Boundary Liquid‐Crystalline Phases under the Effect of the Magnetic Field: A Complete²H and¹³C NMR Study