Thermotropic Liquid Crystals

The aim of this book is to give a unified and critical account of the fundamental aspects of liquid crystals. Preference is given to discussing the assumptions made in developing theories and analyzing experimental data rather than to attempting to compile all the latest results. The book has four parts. Part I is quite descriptive in character and gives a general overview of the various liquid crystalline phases. Part II deals with the macroscopic continuum theory of liquid crystals and gives a systematic development of the theory from a tensorial point of view thus emphasizing the relevant symmetries. Part III concentrates on experiments that provide microscopic information on the orientational behaviour of the molecules. Finally Part IV discusses the theory of the various phases and their attendant phase transitions from both a Landau and a molecular-statistical point of view. Simplifying the various models as far as possible, it critically examines the merits of a molecular-statistical approach.

This book covers developments in the field of thermotropic liquid crystals and their functional importance. It also presents advances related to different sub-areas pertinent to this interdisciplinary area of research. This text brings together research from synthetic scientists and spectroscopists and attempts to bridge the gaps between these areas. New physical techniques that are powerful in characterizing these materials are discussed.

Liquid crystal polymers are sometimes called super polymers--with good reason. Their wide range of exceptional properties and ease of processing make them design candidates for many demanding applications. This new book provides a thorough review of LCP technology with the emphasis on the chemistry, synthesis and characterization of the material in its many variants. Additional chapters cover processing and applications. From the Editor's Preface The field of thermotropic liquid crystalline polymers has grown substantially in the last two decades, with fundamental research, publications, commercial products, and patents. In the 1980's, Dr. Ralph Miano led my colleagues and me at Hoechst Celanese in commercializing the first thermotropic liquid crystalline polymers, based on Dr. Gordon Calundann's composition patents. Today, more than seven companies have produced thermotropic liquid crystalline polymer materials, with at least 50 variants available. Hence, it is timely to compile a comprehensive review on the nature of this type of material and the ongoing progress in this field.... The goals of this book are to summarize previous work, provide new insights into this class of polymers, and add to the understanding of the formation of liquid crystallinity. This book covers a wide range of topics and addresses different disciplines in the field. The chapters are arranged as a learning scheme for the professional, from basic science to applied engineering. The first few chapters summarize the syntheses of various polyester, polyester-amid, and polyimide liquid crystalline polymers. The science and origins of liquid crystal formation are revealed. Next, we introduce the characterizations of these materials by their different chemical and physical aspects. Because most commercially available thermotropic liquid crystalline polymers have been used in the form of composites, we have also incorporated a chapter on polymer blends, detailing blending mechanisms and resultant properties. Two chapters on thermosetting liquid crystalline polymers integrate them with other topics, because of their unique importance and their applications for microelectronics and packaging. The final chapter deals with the engineering and processing aspects of thermoplastic liquid crystalline polymers for a variety of applications.

In 1959, about 1400 compounds forming liquid crystalline phases were known; by 1992, this number had increased to about 50 000. In portable devices like wristwatches, pocket caculators, measuring instruments, and laptop computers the liquid crystal display technology has gained total acceptance and is on the way to encompass the market of colour TV screens. This development makes a volume devoted to liquid crystals in the series Topics in Physical Chemistry desirable. Following the concept of this series, an easy introduction to liquid crystals is given, enabling the reader to understand the basic problems of liquid crystals research and application. Because of the widespread field of different research activities in liquid crystals and applications, various competent authors have been involved in writing chapters on: - Phase types, structures, and chemistry of liquid crystals; - Thermodynamical behavior and physical properties of thermotropic liquid crystals; - Liquid crystalline polymers; - Lyotropic liquid crystals; - Application of liquid crystals in spectroscopy; - Application of liquid crystals in display technology.

This is a new and greatly revised edition of Professor Chandrasekhar's classic book Liquid Crystals, first published in 1977. The subject of liquid crystals has grown into an exciting interdisciplinary research field with important practical applications. This book presents a systematic and self-contained treatment of the physics of the different types of thermotropic liquid crystals - the three classical types, nematic, cholesteric and smectic, and the newly discovered discotic type. Included is a description of the structures of these four main types and their polymorphic modifications, their thermodynamical, optical and mechanical properties and their behaviour under external fields. The basic principles underlying the major applications of liquid crystals in display technology and in thermography are also discussed. This book will be of great value to advanced students and researchers in condensed matter physics, chemical physics, materials science and technology with an interest in the physics, chemistry and applications of liquid crystals.

In recent years, studies by both industry and academic researchers have opened the door to improving performance and reducing costs of these new materials. The particular structure and morphology of LCPs, as well as their peculiar rheological behavior, have stimulated researchers to develop new theoretical models and new characterization and processing techniques to more fully understand and utilize LCPs. Although the scientific literature is very rich in data on the synthetic techniques and on the relations between structure and phase behavior of these new polymers, the understanding of the rheological and processing aspects is still far from satisfactory-particularly in the case of LCP blends. In fact, although an appreciable number of patents and scientific papers have appeared describing the phase behavior, the rheology, and the mechanical properties of many of these polyblends, several aspects of the relations between processing and morphology, and between morphology and properties of these materials are still obscure or even controversial. Now, this new book, written by leading researchers, provides an up-to-date guide and reference to the processing, rheology and applications of pure LCPs and LCP blends. The book concisely reviews the synthetic procedures for the production of LCPs and discusses the rheological behavior and processing methods. Plus, the book examines present and future applications areas of LCPs and LCP blends.

Since the early 1970s, thermotropic liquid crystals have played a central role in molecular electronics and display devices. The discovery of liquid crystal polymers has lead to the development of high tensile strength fibres, and new liquid crystal technologies hold promise for advances in several other areas, such as large area displays for word processors, computer terminals, and temperature-sensing devices. This volume is designed to encourage collaboration among physicists, organic chemists, electronic engineers, and other specialists in the physical sciences in order to facilitate research and development in this field. It provides thorough coverage of the subject by experts in various areas, including detailed treatments of the structure and organization in various liquid crystal phases; the relations between their strongly anisotropic properties and molecular structure; and clear insights into their applications and the underlying physics involved in each. Each chapter begins by examining fundamental concepts, introducing newcomers in the field to the associated terminology and providing a basic understanding of its multidisciplinary nature.