Author: Carlos Heston Ricardo Hunte
Publisher:
ISBN:
Category : Chirality
Languages : en
Pages : 442

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Author: Yuxi Yang
Publisher:
ISBN:
Category :
Languages : en
Pages : 114

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Author: Igor Muševič
Publisher: Springer Science & Business Media
ISBN: 9783540207894
Category : Mathematics
Languages : en
Pages : 320

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This book describes the state of the art of our understanding of liquid-crystal interfaces on a molecular level. The interactions of liquid crystal molecules with a surface play an essential role in the operation of liquid crystal displays (LCD's) and other LC devices that are based on the controllable anchoring of LC molecules on polymer coated surfaces. This book addresses the microscopic interaction between a macromolecule (liquid crystal, polymer) and a wall, using state of the art surface and interface-sensitive experimental techniques, such as Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM), Linear and Nonlinear Optical Microscopy and (Dynamic) Light Scattering (DLS). These experimental techniques were complemented with computer simulations and supra molecular chemistry methods to develop controllable polymeric surfaces.

Author: Pavan Kumar Challa
Publisher:
ISBN:
Category : Liquid crystals
Languages : en
Pages : 139

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This dissertation is mainly divided into three parts. First, the dynamic light scattering measurements on both calamitic and bent-core nematic liquid crystals, carried out in the new split-helix resistive magnet at the National High Magnetic Field Laboratory, Tallahassee is discussed. In a nematic liquid crystal the molecules tend to be aligned along a constant direction, labeled by a unit vector (or "director") n. However, there are fluctuations from this average configuration. These fluctuations are very large for long wavelengths and give rise to a strong scattering of light. The magnetic field reduces the fluctuations of liquid crystal director n. Scattered light was detected at each scattering angle ranging from 0° to 40°. The relaxation rate and inverse scattered intensity of director fluctuations exhibit a linear dependence on field-squared up to 25 Tesla. We also observe evidence of field dependence of certain nematic material parameters. In the second part of the dissertation, magneto-optical measurements on two liquid crystals that exhibit a wide temperature-range amorphous blue phase (BPIII) are discussed. Blue phase III is one of the phases that occur between chiral nematic and isotropic liquid phases. Samples were illuminated with light from blue laser; the incident polarization direction of the light was parallel to the magnetic field. The transmitted light was passed through another polarizer oriented at 90° with respect to the first polarizer and was detected by a photo-detector. Magnetic fields up to 25Tesla are found to suppress the onset of BPIII in both materials by almost 1 degree celcius. This effect appears to increase non-linearly with the field strength. The effect of high fields on established BPIII's is also discussed, in which we find significant hysteresis and very slow dynamics. Possible explanations of these results are discussed. In the third part of the dissertation, magneto-optic measurements on two odd-numbered dimer molecules that form the recently discovered twist-bend nematic (NTB) phase, which represents a new type of 3-dimensional anisotropic fluid with about 10 nm periodicity and accompanied optical stripes are discussed. In twist-bend nematic phase the director follows an oblique helicoid, maintaining a constant oblique angle with the helix axis and experiencing twist and bend. The pitch of the oblique helocoid is in the nanometer range. Light from a red laser was passed normally through the sample placed between crossed polarizers oriented at ±45° with respect to the vertical magnetic field. Optical birefringence was measured from the transmitted light. Magnetic field of B=25T shifts downward the N-NTB phase transitions by almost 1 Celsius. We also show that the optical stripes can be unwound by a temperature and material dependent magnetic induction in the range of B=5-25T. Finally, we propose a Helfrich-Hurault type mechanism for the optical stripe formation. Based on this model we calculate the magnetic field unwinding the optical scale stripes, and find agreement with our experimental results.

Author: Amit Agarwal
Publisher: LAP Lambert Academic Publishing
ISBN: 9783838396750
Category :
Languages : en
Pages : 148

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Liquid crystals are known for their fascinating optical properties. This work describes the experiments on light scattering and theoretical calculations on nonlinear optics in liquid crystals. Light scattering is a powerful tool to study the viscoelastic response of liquid crystals which is an essential parameter for display industry. Both thermotropic and lyotropic systems were probed by light scattering. Thermal nonlinearities in cholesteric liquid crystals are described in this book and various surprising liquid crystal phase transitions in the presence of a laser beam are reported. The work described in the book is based on Ph.D. work carried out by Amit K Agarwal at the Raman Research Institute, India and all intellectual and other legal rights arising out of this work are owned by the Institute and they are acknowledged and protected.

Author: John W. Goodby
Publisher: John Wiley & Sons
ISBN: 3527327738
Category : Technology & Engineering
Languages : en
Pages : 5240

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Book Description
Much more than a slight revision, this second edition of the successful "Handbook of Liquid Crystals" is completely restructured and streamlined, with updated as well as completely new topics, 100% more content and a new team of editors and authors. As such, it fills the gap for a definitive, single source reference for all those working in the field of organized fluids and will set the standard for the next decade. The Handbook's new structure facilitates navigation and combines the presentation of the content by topic and by liquid-crystal type: A fundamentals volume sets the stage for an understanding of the liquid crystal state of matter, while individual volumes cover the main types and forms, with a final volume bringing together the diverse liquid crystal phases through their applications. This unrivaled, all-embracing coverage represents the undiluted knowledge on liquid crystals, making the Handbook a must-have wherever liquid crystals are investigated, produced or used, and in institutions where their science and technology is taught. Also available electronically on Wiley Online Library, www.wileyonlinelibrary.com/ref/holc Volume 1: Fundamentals of Liquid Crystals Volume 2: Physical Properties and Phase Behavior of Liquid Crystals Volume 3: Nematic and Chiral Nematic Liquid Crystals Volume 4: Smectic and Columnar Liquid Crystals Volume 5: Non-Conventional Liquid Crystals Volume 6: Nanostructured and Amphiphilic Liquid Crystals Volume 7: Supermolecular and Polymeric Liquid Crystals Volume 8: Applications of Liquid Crystals

Author: Iam-choon Khoo
Publisher: World Scientific
ISBN: 9814505676
Category : Science
Languages : en
Pages : 440

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Book Description
This is a monograph/text devoted to a detailed treatment of the optical, electro-optical and nonlinear optical properties of all the mesophases of liquid crystals and related processes, phenomena and application principles. Quantitative data on material and optical parameters spanning the ultraviolet, visible, infrared as well as the microwave regimes are presented along with detailed theoretical treatments of basic liquid crystal physics, material properties and nonlinear optics.Starting with a discussion on the basic building blocks of liquid crystalline molecules, the authors proceed to present in a pedagogical manner current theories, experiments, and applications of these unique and important optical properties of liquid crystals. Numerous tables of hard-to-find liquid crystalline parameters, a self-contained chapter on general nonlinear optics, and comprehensive literature review are also included.

Author: Lih-Bin Shih
Publisher:
ISBN:
Category : Liquid crystals
Languages : en
Pages : 420

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Author: Birendra Bahadur
Publisher: World Scientific
ISBN: 9814507091
Category : Science
Languages : en
Pages : 606

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This book reviews comprehensively the technological, scientific, artistic and medical applications of liquid crystals. It starts with the basics of liquid crystals and covers electro-optical, thermo-optical, colour, polymeric, lyotropic, and scientific applications of liquid crystalline materials. It discusses the fabrication and operational principles of a full range of liquid crystal displays including dynamic scattering, twisted nematic, supertwisted nematic, dichroic, smectic A, ferroelectric, polymer dispersed, light valve, active matrix, etc., in detail. It also covers the emerging applications of liquid crystals such as optical computing, nonlinear optics, decorative and visual arts. The detailed chapters on classification, theory, chemical structure, physical properties and surface alignment of liquid crystals facilitate the basic understanding of the science behind LCDs and other uses of liquid crystals. The chapters on liquid crystal polymers and lyotropic liquid crystals, give deep insight into these areas. The potential uses and applications are also described in detail.

Author: Stephen D. Jacobs
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 736

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