Unconventional Liquid Crystals and Their Applications


Book Description

The work focuses on recent developments of the rapidly evolving field of Non-conventional Liquid Crystals. After a concise introduction it discusses the most promising research such as biosensing, elastomers, polymer films , photoresponsive properties and energy harvesting. Besides future applications it discusses as well potential frontiers in LC science and technology.




Synthesis and Characterization of Photochemically Tunable Chiral Materials for Optically Addressed Cholesteric Displays


Book Description

Liquid crystal displays are widely used in many electronic devices. To produce an image the displays are electronically addressed through complex electrode patterning. The electrode patterning is costly due to the development of drive chips and software and adds to the bulk of the display in order to house the control circuitry and power supply. In effort to reduce the cost of cholesteric displays, the development of a photocontrolled cholesteric state was undertaken. Such a state would eliminate the need for electronic control, enabling the display to be optically addressed by the addition of a photochemically tunable chiral dopant. This work focuses on the synthesis of 4-({2,2'-[(4-hydroxyphenyl) diazenyl]-1,1'-binaphthalenyl} diazenyl)phenol and modified derivatives for use as photochemically tunable chiral dopants in cholesteric displays. In detail, the synthesis, characterization and preliminary evaluation of the materials as dopants are reported. Some doped mixtures exhibit a tunable Bragg reflection of over 2,500 nm, while others have been optimized to only have tunable reflection within the visible spectrum. The details of a prototype display based on the properties of these materials are also included.




Liquid Crystals


Book Description

Liquid Crystals - Self-Organized Soft Functional Materials for Advanced Applications is focused on both theoretical models and experimental results, pointing out the chemical and physical properties (thermodynamics, electro-optic switching behavior, and non-linear optic phenomena) of liquid crystals used in a wide range of devices. In this respect, the chapters cover the following topics: chemical structure and phase transitions in bent-core liquid crystals, phase and structural behavior of liquid crystals used to align carbon nanotubes, molecular alignment, and photorefractive effect in the ferroelectric phase, which has the potential to be used as transistors, for image storage, and in optical signal processing. It is expected that the book will be of interest to researchers in academia and industries, as well as advanced students.







Handbook of Liquid Crystals, Fundamentals


Book Description

The Handbook of Liquid Crystals is a unique compendium of knowledge on all aspects of liquid crystals. In over 2000 pages the Handbook provides detailed information on the basic principles of both low- and high-molecular weight materials, as well as the synthesis, characterization, modification, and applications (such as in computer displays or as structural materials) of all types of liquid crystals. The five editors of the Handbook are internationally renowned experts from both industry and academia and have drawn together over 70 leading figures in the field as authors. The four volumes of the Handbook are designed both to be used together or as stand-alone reference sources. Some users will require the whole set, others will be best served with a selection of the volumes. Volume 1 deals with the basic physical and chemical principles of liquid crystals, including structure-property relationships, nomenclature, phase behavior, characterization methods, and general synthesis and application strategies. As such this volume provides an excellent introduction to the field and a powerful learning and teaching tool for graduate students and above. Volume 2 concentrates on low-molecular weight materials, for example those typically used in display technology. A high quality survey of the literature is provided along with full details of molecular design strategies, phase characterization and control, and applications development. This volume is therefore by far the most detailed reference source on these industrially very important materials, ideally suited for professionals in the field. Volume 3 concentrates on high-molecular weight, or polymeric, liquid crystals, some of which are found in structural applications and others occur as natural products of living systems. A high-quality literature survey is complemented by full detail of the synthesis, processing, analysis, and applications of all important materials classes. This volume is the most comprehensive reference source on these materials, and is therefore ideally suited for professionals in the field.







Electrically-tunable Colors of Chiral Liquid Crystals for Photonic and Display Applications


Book Description

Electrically tunable colors with chiral liquid crystal materials have been discussed in this thesis. The switchable color device can be used as a color filter and may be an important step toward eco-friendly color reflective displays. The first approach in achieving electrically tunable color is a polymer-stabilized cholesteric liquid crystal. The selected Bragg reflective wavelength can be electrically switched to reflect blue or green from a cell initially reflecting a red color. The color change is a result of the compression of the helical pitches in planar layers in response to the applied voltage. The unique feature of the polymer stabilization is in the fact that the electrically switched colors preserve good reflectance and the colors are reversible with voltage ramping. The polymer-stabilized cholesteric display exhibits anisotropic reflection and has a reflected color which is independent of temperature. A second method is a polymer-stabilized blue phase liquid crystal, in which the Bragg reflected color of the blue phase can be switched to reflect a second color through the electrostriction effect. The phase-separated three-dimensional polymer network transcribes the cubic structure of a BP liquid crystal and restrains the deformation from cubic lattice by the external electric field.




Chemistry of Discotic Liquid Crystals


Book Description

The self-contained properties of discotic liquid crystals (DLCs) render them powerful functional materials for many semiconducting device applications and models for energy and charge migration in self-organized dynamic functional soft materials. The past three decades have seen tremendous interest in this area, fueled primarily by the possibility of creating a new generation of organic semiconductors and wide viewing displays using DLCs. While a number of books on classical calamitic liquid crystals are available, there are, as yet, no books that are dedicated exclusively to the basic design principles, synthesis, and physical properties of DLCs. The first reference book to cover DLCs, Chemistry of Discotic Liquid Crystals: From Monomers to Polymers highlights the chemistry and thermal behavior of DLCs. Divided into six chapters, each with a general description, background, and context for the concepts involved, the book begins with a basic introduction to liquid crystals, describing molecular self-assembly and various types of liquid crystals. It outlines their classification, covers their history and general applications, and focuses on DLCs and their discovery, structure, characterization, and alignment. The book goes on to examine the chemistry and physical properties of various monomeric DLCs, including 25 sections describing the synthesis and mesomorphic properties of monomeric DLCs formed by different cores. The bulk of the book covers the chemistry and mesomorphism of discotic dimers, oligomers, and polymers and concludes with a look at some applicable properties of DLCs. A comprehensive and up-to-date resource, this book is designed to be accessible and of value not just for students and researchers but also to the directors and principal investigators working in this field, providing the foundation and fuel to advance this fast-growing technological field.