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Liquid crystal

About: Liquid crystal is a(n) research topic. Over the lifetime, 100576 publication(s) have been published within this topic receiving 1449858 citation(s).

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Journal ArticleDOI
Abstract: The synthesis, characterization, and proposed mechanism of formation of a new family of silicatelaluminosilicate mesoporous molecular sieves designated as M41S is described. MCM-41, one member of this family, exhibits a hexagonal arrangement of uniform mesopores whose dimensions may be engineered in the range of - 15 A to greater than 100 A. Other members of this family, including a material exhibiting cubic symmetry, have ken synthesized. The larger pore M41S materials typically have surface areas above 700 m2/g and hydrocarbon sorption capacities of 0.7 cc/g and greater. A templating mechanism (liquid crystal templating-LCT) in which surfactant liquid crystal structures serve as organic templates is proposed for the formation of these materials. In support of this templating mechanism, it was demonstrated that the structure and pore dimensions of MCM-41 materials are intimately linked to the properties of the surfactant, including surfactant chain length and solution chemistry. The presence of variable pore size MCM-41, cubic material, and other phases indicates that M41S is an extensive family of materials.

10,033 citations

01 Feb 1974
Abstract: Part 1 Liquid crystals - main types and properties: introduction - what is a liquid crystal? the building blocks nematics and cholesterics smectics columnar phases more on long-, quasi-long and short-range order remarkable features of liquid crystals. Part 2 Long- and short-range order in nematics: definition of an order parameter statistical theories of the nematic order phenomonological description of the nematic-isotopic mixtures. Part 3 Static distortion in a nematic single crystal: principles of the continuum theory magnetic field effects electric field effects in an insulating nematic fluctuations in the alignment hydrostatics of nematics. Part 4 Defects and textures in nematics: observations disclination lines point disclinations walls under magnetic fields umbilics surface disclinations. Part 5 Dynamical properties of nematics: the equations of "nematodynamics" experiments measuring the Leslie co-efficients convective instabilities under electric fields molecular motions. Part 6 Cholesterics: optical properties of an ideal helix agents influencing the pitch dynamical properties textures and defects in cholesterics. Part 7 Smectics: symmetry of the main smectic phases continuum description of smectics A and C remarks on phase and precritical phenomena.

9,603 citations

26 Nov 1998
Abstract: Part I: Fundamentals 1. Introduction to Complex Fluids 1.3 Rheological Measurements and Properties 1.4 Kinematics and Stress 1.5 Flow, Slip, and Yield 1.6 Structural Probes of Complex Fluids 1.7 Computational Methods 1.8 The Stress Tensor 1.9 Summary 2. Basic Forces 2.1 Intoduction 2.3 Van der Waals Interactions 2.4 Electrostatic Interactions 2.5 Hydrogen-Bonding, Hydrophobic, and Other Interactions 2.6 Summary Part II: Polymers, Glassy Liquids, and Polymer Gels 3. Polymers 3.1 Introduction 3.2 Equilibrium Properties 3.3 Intrinsic Viscosity and Overlap Concentration 3.4 Elementary Molecular Theories 3.5 Linear Viscoelasticity and Time-Temperature Superposition 3.6 The Rheology of Dilute Polymer Solutions 3.7 The Rheology of Entangled Polymers 3.8 Summary 4. Glassy Liquids 4.1 Introduction 4.2 Phenomenology of the Glass Transition 4.3 Free-Volume Theories 4.4 Entropy Theories 4.5 Nonlinear Relaxation and Aging 4.6 Mode-Coupling Theory and Colloidal Hard-Sphere Glasses 4.7 Analog Models 4.8 Rheology of Glassy Liquids 4.9 Summary 5. Polymer Gels 5.1 Introduction 5.2 Gelation Theoies 5.3 Rheology of Chemical Gels and Near-Gels 5.4 Rheology of Physical Gels 5.5 Summary Part III: Suspensions 6. Particulate Suspensions 6.1 Introduction 6.2 Hard, and Slightly Deformable Spheres 6.3 Nonspherical Particles 6.4 Electrically Charged Particles 6.5 Particles in Viscoelastic Liquids: "Filled Melts" 6.6 Summary 7. Particulate Gels 7.1 Introduction 7.2 Particle Interactions in Suspensions 7.3 Rheology of Particulate Gels 7.4 Summary 8. Electro- and Magneto-Responsive Suspensions 8.1 Introduction 8.2 Electrorheological Fluids 8.3 Magnetorheological Fluids 8.4 Ferrofluids 8.5 Summary 9. Foams, Emulsions, and Blends 9.1 Introduction 9.2 Emulsion Preparation 9.3 Rheology of Emulsions and Immiscible Blends 9.4 Structure and Coarsening of Foams 9.5 Rheology of Foams 9.6 Summary Part IV: Liquid Crystals and Self-Assembling Fluids 10. Liquid Crystals 10.1 Introduction 10.2 Nematics 10.3 Cholesterics: Chiral Nemantics 10.4 Smectics 10.5 Summary 11. Liquid Crystalline Polymers 11.1 Introduction 11.2 Molecular Characteristics of Liquid Crystalline Polymers 11.3 Flow Properties of Nematic LCP's 11.4 Molecular Dynamics of Polymeric Nematics 11.5 Molecular Theory for the Rheology of Polymeric Nematics 11.6 Summary 12. Surfactant Solutions 12.1 Introduction 12.2 Methods of Predicting Microstructures 12.3 Disordered Micellar Solutions 12.4 Surfactant Liquid Crystals 12.5 Summary 13. Block Copolymers 13.1 Introduction 13.2 Thermodynamics of Block Copolymers 13.3 Rheology and Shear-Aligning of Block Copolymers 13.4 Summary Appendix: Momentum-Balance Equations in the Absence of Inertia

3,763 citations

Journal ArticleDOI
Abstract: Ferroelectric smectic C (FSC) liquid crystals are used in a simple new geometry that allows the spontaneous formation of either of two surface‐stabilized smectic C monodomains of opposite ferroelectric polarization. These domains are separated by well‐defined walls which may be manipulated with an applied electric field. The resulting electro‐optic effects exhibit a unique combination of properties: microsecond dynamics, threshold behavior, symmetric bistability, and a large electro‐optic response.

2,267 citations

Journal ArticleDOI
TL;DR: This work shows the stabilization of blue phases over a temperature range of more than 60 K including room temperature (260–326 K), and demonstrates an electro-optical switching with a response time of the order of 10−4 s for the stabilized blue phases at room temperature.
Abstract: Blue phases are types of liquid crystal phases that appear in a temperature range between a chiral nematic phase and an isotropic liquid phase. Because blue phases have a three-dimensional cubic structure with lattice periods of several hundred nanometres, they exhibit selective Bragg reflections in the range of visible light corresponding to the cubic lattice. From the viewpoint of applications, although blue phases are of interest for fast light modulators or tunable photonic crystals, the very narrow temperature range, usually less than a few kelvin, within which blue phases exist has always been a problem. Here we show the stabilization of blue phases over a temperature range of more than 60 K including room temperature (260–326 K). Furthermore, we demonstrate an electro-optical switching with a response time of the order of 10−4 s for the stabilized blue phases at room temperature.

1,799 citations

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