Electro-optical Investigations of Liquid Crystalline Mixtures PDF Download

Author: Mohammad Reza Daj
Publisher:
ISBN:
Category :
Languages : en
Pages : 224

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Author: Jennifer Kirchhoff
Publisher:
ISBN:
Category :
Languages : en
Pages : 157

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ABSTRACT: Liquid crystal phases exhibit physical characteristics that lie between those of liquid and crystal phases. The many liquid crystal sub-phases are defined based on the degree of positional and orientational ordering the molecules have and the materials that make up these liquid crystal phases. This thesis presents a study of the molecular packing and physical properties of complex liquid crystal phases using dopants to better examine the stability and packing mechanisms of these phases. It also looks at the dispersion of quantum dots in liquid crystal materials, examining the electro-optical properties of the mixtures. The main goal of this thesis is to examine the effects of dopants on the properties of liquid crystal phases using optical microscopy, differential scanning calorimetry, electro-optical measurements, and X-ray scattering. For those mixtures with quantum dots fluorescence microscopy and photoluminescence measurements were also conducted. Rod-like liquid crystals are commonly used in display applications when the material is in a nematic liquid crystal phase, which is the least ordered phase exhibiting no positional ordering. The more complicated chiral smectic liquid crystal phases, which have a one dimensional layer structure, show potential for faster and tri-stable switching. A chiral rod-like liquid crystal material is doped with both chiral and achiral rod-like liquid crystals to examine the stability of one of the chiral smectic sub-phase, the SmC*FI1 phase. This phase consists of tilted molecules rotating about the cone defined by the tilt angle with a periodicity of three layers and an overall helical structure.

Author: L.M. Blinov
Publisher: Springer Science & Business Media
ISBN: 1461226929
Category : Science
Languages : en
Pages : 477

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Electrooptic effects provide the basis for much liquid-crystal display technology. This book, by two of the leaders in liquid-crystal research in Russia, presents a complete and accessible treatment of virtually all known phenomena occurring in liquid crystals under the influence of electric fields.

Author: Lev Mikhaĭlovich Blinov
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 376

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Author: L. C. Scala
Publisher:
ISBN:
Category :
Languages : en
Pages : 69

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The usefulness of optical devices, whose sensors consist of cholesteric liquid crystal combinations, is directly dependent upon the reproducibility of their color responses to changes in temperature and to electric fields. Many of the processes by which cholesteric liquid crystals lose their valuable optical properties were identified and steps taken to diminish or eliminate their effects. Oleyl cholesteryl carbonate, one of the essential components of field- and heat-sensitive liquid crystal mixtures, was found to decompose spontaneously to give CO and CO2 at a relatively small rate, which may still be too large in the case of applications involving sealed, evacuated systems. The thermal hysteresis observed in high temperature-sensitive liquid crystals was mainly dependent upon the material composition of the system and on the operating range. On shearing, cholesteric liquid crystal layers lost color intensity, but the wavelength of their maximum reflectance did not change appreciably. The rate of intensity recovery after cessation of shearing was linear with the logarithm of time. The main degradative process is brought about by the combined and cumulative influences of ultraviolet light, oxygen and air-borne particulates; as a result, the color-bearing cholesteric structure is changed into a non-colored texture and the color responses are lost. This drawback was remedied by incorporating ultraviolet energy absorbers and polymeric protectants into the liquid crystal combinations. With these modified systems the useful life of cholesteric liquid crystal sensing systems was prolonged by several months. (Author).

Author: Pankaj Kumar Choudhury
Publisher: BoD – Books on Demand
ISBN: 9535138715
Category : Science
Languages : en
Pages : 276

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Liquid crystals exhibit amazingly interesting properties that make them indispensable for several technological applications. The book Liquid Crystals - Recent Advancements in Fundamental and Device Technologies is aimed to focus on various aspects of research and development that liquid crystal mediums have come across in recent years. This would be ranging from the physical and chemical properties to the important applications that the liquid crystals have in our everyday life. It is expected that the book will make the expert researchers to be abreast of recent research advancements, whereas the novice researchers will benefit from both the conceptual understanding and the recent developments in the area. Multitudes of research themes and directions pivoted to liquid crystals remain the essence, which the readers would get the glimpse of and move ahead for further investigations.

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: Iam-Choon Khoo
Publisher: John Wiley & Sons
ISBN: 1119705827
Category : Technology & Engineering
Languages : en
Pages : 420

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The latest edition of the leading resource on the properties and applications of liquid crystals In the newly revised Third Edition of Liquid Crystals, Professor Iam Choon Khoo delivers a comprehensive treatment of the fundamentals and applied aspects of optical physics, light scattering, electro-optics, and non-linear optics of liquid crystals. The book's opening chapters include coverage of the foundational physics and optical properties of liquid crystals and lead to more advanced content on the display, photonics and nonlinear optics applications of liquid crystals. New topics, including photonic crystals, metamaterials, ultrafast nonlinear optics, and fabrication methods for massive cholesteric and blue phase liquid crystals are discussed at length. Analytical methods and experimental observations of nonlinear light propagation through liquid crystalline and anisotropic materials and devices are also discussed. Liquid Crystals offers an insightful and unique treatment of the nonlinear optics of liquid crystals. New and expanded sections round out this new edition and add to the most up-to-date resource on this topic available today. The book also includes: A thorough introduction to liquid crystals, including their molecular structures, chemical compositions, order parameter, phase transition, and free energies Practical discussions of nematic, cholesteric, smectic, and ferroelectric liquid crystals, and explorations of linear and nonlinear light scattering in these phases. A detailed quantum mechanical treatment of the linear and nonlinear electronic optical response of liquid crystal molecules to optical fields. A self-contained discussion of the fundamentals of nonlinear optics/photonics and comprehensive review of all liquid crystalline materials-based nonlinear optical processes and applications. The latest edition of Liquid Crystals is an indispensable resource for graduate students, professors, research scientists and engineers in industrial or government laboratories. It's also an ideal reference for anyone seeking a one-stop textbook with complete coverage of the optical, electro-optical, and non-linear optical properties and processes of liquid crystals.

Author: I. Jánossy
Publisher: Springer
ISBN: 9789401054034
Category : Science
Languages : en
Pages : 234

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Book Description
In 1988 physicists and chemists commemorated the centenary of the discovery of the first liquid crystals. Fora long period after this discovery, although many significant results were found, liquid crystal research remained a marginal topic of condensed matter physics. The situation changed in the sixties. At that time the remarkable electro-optical properties of liquid crystals were recognized and found soon widespread application in numeric displays. From a more fundamental point of view, the interest in disordered systems. increased in general at the same time. Liquid crystals represented an important dass of such systems. Among others, phase transitions, hydrodynamics and topological defects occurring in them attracted considerable attention. The connection between the liquid-crystalline state and the structure of biological membranes stimulated a Iot of works also. In the present volume we discuss a relatively new and rapidly developing branch of the fi. eld, namely nonlinear optical effects in liquid crystals. Optical studies have always played a signifi. cant role in liquid crystal science. Research of optical nonlinearities in liquid crystals began at the end of the sixties. Since then it became a powerful tool in the investigation of symmetry properties, interfacial phenomena or dynamic behaviour. Furthermore, several new aspects of nonlinear processes were demonstrated and studied extensively in liquid crystals. The subject covered in this book is therefore of importance both for liquid crystal research and for nonlinear optics itself. The term "nonlinear optics" is used here in a broad sense.

Author: Lev Mihajlovič Blinov
Publisher:
ISBN: 9780835786331
Category :
Languages : en
Pages : 363

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