Download or read book Atlas Of Vibrational Spectra Of Liquid Crystals written by Marco P Fontana and published by World Scientific. This book was released on 1988-08-01 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: This atlas is the first one in the field of vibrational spectroscopy of polyatomic molecules. It is divided into two paragraphs. The first deals with the theory of vibrational spectroscopy in a concise form and considers the most important spectroscopical parameters — frequencies, bandshape and intensities. The second paragraph is dedicated to the infrared (2000-400 cm-1), far infrared (400-40 cm-1) and Raman (2000-10 cm-1) spectra of about hundred different mesomorphic materials with various molecular structure. The polarized IR spectra of the most important liquid crystals is also included. In the second paragraph the assignment of the IR bands to the corresponding intramolecular vibrations is also reported. Almost all spectra is registrated and analysed for the first time. The major important features are: 1. Registration and analysis (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phases; 2. Registration (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phase in polarized IR light. Polarized vibrational spectra are very important for clarification of the molecular structure; 3. Assignment (for the first time) of the IR bands of the most important liquid crystalline materials to the corresponding vibrations.

Download or read book Atlas of Vibrational Spectra of Liquid Crystals written by Paraskeva Simova and published by World Scientific. This book was released on 1988 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: This atlas is the first one in the field of vibrational spectroscopy of polyatomic molecules. It is divided into two paragraphs. The first deals with the theory of vibrational spectroscopy in a concise form and considers the most important spectroscopical parameters ? frequencies, bandshape and intensities. The second paragraph is dedicated to the infrared (2000?400 cm-1), far infrared (400?40 cm-1) and Raman (2000?10 cm-1) spectra of about hundred different mesomorphic materials with various molecular structure. The polarized IR spectra of the most important liquid crystals is also included. In the second paragraph the assignment of the IR bands to the corresponding intramolecular vibrations is also reported. Almost all spectra is registrated and analysed for the first time. The major important features are: 1. Registration and analysis (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phases; 2. Registration (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phase in polarized IR light. Polarized vibrational spectra are very important for clarification of the molecular structure; 3. Assignment (for the first time) of the IR bands of the most important liquid crystalline materials to the corresponding vibrations.

Download or read book The Molecular Dynamics of Liquid Crystals written by G.R. Luckhurst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid-crystalline phases are now known to be formed by an ever growing range of quite diverse materials, these include those of low molecular weight as well as the novel liquid-crystalline polymers, such phases can also be induced by the addition of a solvent to amphiphilic systems leading to lyotropic liquid crystals. Irrespective of the structure of the constituent molecules these numerous liquid-cl)'Stailine phases are characterised by their long range orientational order. In addition certain phases exhibit elements of long range positional order. Our understanding, both experimental and theoretical, at the molecular level of the static behaviour of these fascinating and important materials is now well advanced. In contrast the influence of the long range order; both orientational and positional, on the molecular dynamics in liquid Cl)'Stais is less well understood. In an attempt to address this situation a NATO Advanced Study Institute devoted to liquid ctystal dynamics was held at n Ciocco, Barga, Italy in September 1989. This brought together experimentalists and theoreticians concerned with the various dynamical processes occurring in all liquid crystals. The skills of the participants was impressively wide ranging; they spanned the experimental techniques used in the study of molecular dynamics, the nature of the systems investigated and the theoretical models employed to understand the results. While much was learnt it was also recognised that much more needed to be done in order to advance our understanding of molecular dynamics in liquid Cl)'Stais.

Download or read book Long lived Probes to Study the Dynamics of Liquid Crystals by Ultrafast Infrared Vibrational Spectroscopy written by Kathleen P. Sokolowsky and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nematic liquid crystals have been widely studied in the context of practical applications and the nature of phase transitions. Above the nematic-isotropic phase transition temperature (TNI), orientational fluctuations are correlated; the existence of these pseudonematic domains in the isotropic phase dominate the dynamic properties of the bulk liquid. To examine the influence of pseudonematic ordering on the local dynamics, ultrafast infrared (IR) spectroscopies were employed. Two dimensional (2D) vibrational echo spectroscopy supplies information on the spectral diffusion of a vibrational probe molecule. Spectral diffusion is the process by which the frequency of an oscillator changes as the liquid structure about it evolves; it is characterized by the frequency-frequency correlation function (FFCF). The FFCF directly relates the frequency fluctuations of the probe molecule to the dynamics of the liquid structure surrounding it. The model nematic liquid crystal system selected is 4-cyano-4'-pentylbiphenyl (5CB); 5CB contains a nitrile group which can act as the vibrational probe. Examination of the natural abundance carbon-13 nitrile stretch allows for thicker samples, mitigating heating effects. Unfortunately, the vibrational lifetime of the carbon-13 stretch is short, and spectral diffusion is not nearly complete in the experimental window. Two novel extended lifetime vibrational probes similar in structure to 5CB were synthesized. A small amount of either molecule can be added to 5CB to probe the local structure dynamics. OHD-OKE experiments were performed on the doped solutions confirm that the addition of vibrational probe molecule does not significantly perturb the pseudonematic domains of 5CB. Temperature dependent 2D IR experiments were conducted on 5CB and 4-pentylbiphenyl (5B). 5B is molecularly very similar to 5CB, but is not a liquid crystal. The spectral diffusion dynamics in the two liquid are remarkably similar far removed from the liquid crystal phase transition. Close to TNI, the dynamics in 5CB slow down dramatically. The time constants for spectral diffusion are shown to diverge as a[T*/(T-T*)]^1/2. The temperature dependence of the time constants matches that of the size of the pseudonematic domains, not the orientational relaxation time for the domains. Two more liquid crystals are shown to have the same behavior approaching their respective phase transitions, suggesting the divergence may be universal for rod-shaped nematogens. Even at temperatures very close to TNI, spectral diffusion in liquid crystals is complete on the order of a few nanoseconds. This is drastically different than the time for total orientational relaxation which is multiple orders of magnitude slower. The complete randomization of pseudonematic domains is not required for the vibrational probe to sample all structures that contribute to the inhomogeneous line shape. A mode coupling model is constructed for the FFCF to describe spectral diffusion in terms of coupling to large wave vector density fluctuations and orientational fluctuations. The source of spectral diffusion is proposed to be small wave vector density fluctuations, which critically slow as TNI is approached.

Download or read book Advances in Liquid Crystals written by Glenn H. Brown and published by Academic Press. This book was released on 2013-10-22 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Liquid Crystals, Volume 2 covers the study of lyotropic and thermotropic liquid crystals. The five articles in this volume discuss topics such as the effects of change in molecular geometry on the properties of liquid crystals formed by nonamphiphilic (thermotropic) compounds; aspects of the physics and chemistry of cholesteric liquid crystals with respect to temperature dependence and temperature sensitivity of the selective reflection of visible light; arrangements of emulsifier molecules and the interaction between the different components in emulsions; the type of information about liquid crystals obtained from vibrational spectroscopy; and the continuum theory of liquid crystals as it applies to static equilibrium. The book will be invaluable to materials engineers, inventors, physicists, and researchers in the field of electronics.

Download or read book Applications of Liquid Crystals written by G. Meier and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past ten years liquid crystals have attracted much interest and considerable progress has been made with respect to our knowledge in this field. The recent development was initiated mainly by the work of J. L. Fergason and G. H. Heilmeier, who pointed out the importance of liquid crystals for thermographic and electro optic applications. The first part of this book is a brief introduction to the physics of liquid crystals. The structures and properties of the three basic types of liquid crystals are discussed. A special paragraph is devoted to electric-field effects, which are important in display applications. The chapter on Scientific Applications gives an insight into the potential applications of liquid crystals in fundamental research, with special emphasis on explaining the principles involved. Two groups of potential applications are discussed in detail: 1. the use of liquid crystals as anisotropic solvent for the determination of molecular properties by means of spectroscopy, and 2. their use in analytical chemistry, particularly in gas chromatography. The reverse process involves the use of the dissolved molecules as microscopic probes in the investigation of the dynamical molecular structure of anisotropic fluid systems (e.g. biological membranes). This extremely important technique is also described.

Download or read book The Physics of Liquid Crystals written by P. G. de Gennes and published by Oxford University Press. This book was released on 1993 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition of the classic text incorporates the many advances in knowledge about liquid crystals that have taken place since its initial publication in 1974. Entirely new chapters describe the types and properties of liquid crystals in terms of both recently discovered phases and current insight into the nature of local order and isotropic-to-nematic transition. There is an extensive discussion of the symmetrical, macroscopic, dynamic, and defective properties of smectics and columnar phases, with emphasis on order-of-magnitude considerations, all illustrated with numerous descriptions of experimental arrangements. The final chapter is devoted to phase transitions in smectics, including the celebrated analogy between smectic A and superconductors. This new version's topicality and breadth of coverage will ensure that it remains an indispensable guide for researchers and graduate students in mechanics and engineering, and in chemical, solid state, and statistical physics.

Download or read book Liquid Crystals Fundamentals written by Shri Singh and published by World Scientific. This book was released on 2002-11-05 with total page 549 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystals are partially ordered systems without a rigid, long-range structure. The study of these materials covers a wide area: chemical structure, physical properties and technical applications. Due to their dual nature — anisotropic physical properties of solids and rheological behavior of liquids — and easy response to externally applied electric, magnetic, optical and surface fields liquid crystals are of greatest potential for scientific and technological applications. The subject has come of age and has achieved the status of being a very exciting interdisciplinary field of scientific and industrial research.This book is an outgrowth of the enormous advances made during the last three decades in both our understanding of liquid crystals and our ability to use them in applications. It presents a systematic, self-contained and up-to-date overview of the structure and properties of liquid crystals. It will be of great value to graduates and research workers in condensed matter physics, chemical physics, biology, materials science, chemical and electrical engineering, and technology from a materials science and physics viewpoint of liquid crystals.

Download or read book Physical Properties of Liquid Crystals written by George W. Gray and published by John Wiley & Sons. This book was released on 2009-08-14 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook is a unique compendium of knowledge on all aspects of the physics of liquid crystals. In over 500 pages it provides detailed information on the physical properties of liquid crystals as well as the recent theories and results on phase transitions, defects and textures of different types of liquid crystals. An in-depth understanding of the physical fundamentals is a prerequisite for everyone working in the field of liquid crystal research. With this book the experts as well as graduate students entering the field get all the information they need.

Download or read book Vibrational Spectroscopy of Liquid Crystals written by Nikolaĭ Kirov and published by . This book was released on 1984 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Magnetic Resonance of Liquid Crystals written by J.W. Emsley and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: The liquid crystalline state has been known for about a century and has been studied by many techniques. Nuclear magnetic resonance has been used to study mesophases for thirty years, but it has been in very recent years that advances in this form of spectroscopy have led to a rapid growth in its applications to the study both of liquid crystals and of solutes dissolved in them. It has become apparent that no other method of studying liquid crystals can yield such a wealth of data and it is unrivalled as a means of probing the behaviour of the molecules in mesophases. There has also been a steady increase in the study of the shape of small molecules dissolved in liquid crystals via the analysis of their NMR spectrum. In fact, the study of solutes was until recently regarded as a separate activity to the study of liquid crystals themselves, but this artificial division arose only from the gap between the large amount of information that could be derived from the spectrum of a small molecule and the rather meagre data set obtainable from the spectra of liquid crystals. This gap has, however, narrowed and it is now possible to derive a very detailed picture of the structure and orientational ordering of the large molecules typical of those which form liquid crystals. There has also been a rapid growth of interest in the liquid crystalline state.

Download or read book Advances in Liquid Crystals written by Glenn H. Brown and published by Academic Press. This book was released on 2013-10-22 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Liquid Crystals, Volume 5 is a collection of scientific essays that focuses on the developments and applications in the field of liquid crystal science. The text begins with an article about the role of liquid crystals in living systems. The subjects covered in this article include the properties of phospholipids, lipid order parameters, lipid diffusion, and the movements of proteins in model and natural biomembranes. The second essay discusses the use of Mossbauer techniques to lyotropic liquid crystals. Such a method provides a list of characteristics of the crystals in focus. Another topic of interest is the theoretical and experimental aspects of microemulsions. The section that follows describes the carbonaceous mesophases and disclination structures. Types of disclination such as wedge disclination, twist disclinations, and disclinations arrays are covered. The neutron incoherent scattering is the focus of the last essay in the book. The book will provide valuable insights for scientists, developer of crystal displays, students, and researchers in the field of chemistry.

Download or read book Structure and Properties of Liquid Crystals written by Lev M. Blinov and published by Springer Science & Business Media. This book was released on 2010-10-26 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book by Lev M. Blinov is ideal to guide researchers from their very first encounter with liquid crystals to the level where they can perform independent experiments on liquid crystals with a thorough understanding of their behaviour also in relation to the theoretical framework. Liquid crystals can be found everywhere around us. They are used in virtually every display device, whether it is for domestic appliances of for specialized technological instruments. Their finely tunable optical properties make them suitable also for thermo-sensing and laser technologies. There are many monographs written by prominent scholars on the subject of liquid crystals. The majority of them presents the subject in great depth, sometimes focusing on a particular research aspect, and in general they require a significant level of prior knowledge. In contrast, this books aims at an audience of advanced undergraduate and graduate students in physics, chemistry and materials science. The book consists of three parts: the first part, on structure, starts from the fundamental principles underlying the structure of liquid crystals, their rich phase behaviour and the methods used to study them; the second part, on physical properties, emphasizes the influence of anisotropy on all aspects of liquid crystals behaviour; the third, focuses on electro-optics, the most important properties from the applications standpoint. This part covers only the main effects and illustrates the underlying principles in greater detail. Professor Lev M. Blinov has had a long carrier as an experimentalist. He made major contributions in the field of ferroelectric mesophases. In 1985 he received the USSR state prize for investigations of electro-optical effects in liquid crystals for spatial light modulators. In 1999 he was awarded the Frederiks medal of the Soviet Liquid Crystal Society and in 2000 he was honoured with the G. Gray silver medal of the British Liquid Crystal Society. He has held many visiting academic positions in universities and laboratories across Europe and in Japan.

Download or read book Nuclear Magnetic Resonance of Liquid Crystals written by Ronald Y. Dong and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystals have become ubiquitous in the displays for electronic devices, ranging from wrist watches to laptop computers. Nuclear magnetic resonance is one of the important mechanisms for determining their structures tures and properties. This book covers NMR techniques used in studying liquid crystals and present up to date results from such studies. Ronald Dong has worked on NMR in liquid crystals for much of his professional career. Topics covered include: Nuclear spin dynamics, orientational order, molecular field theories of liquid-crystal molecules, nuclear spin relaxation, spin relaxation, rotational and translational dynamics, internal dynamics of liquid-crystal molecules, NMR in liquid crystals; an appendix covers rotations, Euler angles and Wigner rotation matrices.

Download or read book Unconventional Liquid Crystals and Their Applications written by Wei Lee and published by Walter de Gruyter GmbH & Co KG. This book was released on 2021-07-19 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Physics of Liquid Crystalline Materials written by Chor-San Heng Khoo and published by CRC Press. This book was released on 1991-12-16 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is based on lectures delivered at the "summer school" held in October 1988. Papers deal with microscopic properties, collective phenomena (elastic properties, hydrodynamics, linear and nonlinear optics . . . ), and such diverse topics as NMR studies of liquid crystals, orientational disorder and dynamics, rheology of layered liquid crystals, light scattering. Minimal index. Annotation copyrighted by Book News, Inc., Portland, OR

Download or read book Smectic and Columnar Liquid Crystals written by Patrick Oswald and published by CRC Press. This book was released on 2005-12-09 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on graduate lectures given by the authors, Smectic and Columnar Liquid Crystals: Concepts and Physical Properties Illustrated by Experiments examines lamellar (smectic) and columnar liquid crystals, which, in addition to orientational order, possess 1D, 2D or 3D positional order. Topics include rheology and plasticity, ferroelectricity, analogies with superconductors, hexatic order and 2D-melting, equilibrium shapes, facetting, and the Mullins-Sekerka instability, as well as phase transitions in free films and membrane vibrations. Nematic and cholesteric liquid crystals are covered by the authors in a separate volume entitled Nematic and Cholesteric Liquid Crystals: Concepts and Physical Properties Illustrated by Experiments.