Download or read book Assembly Elasticity and Structure of Lyotropic Chromonic Liquid Crystals and Disordered Colloids written by Zoey S. Davidson and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes experiments which explore the structure and dynamics in two classes of soft materials: lyotropic chromonic liquid crystals and colloidal glasses and super-cooled liquids.The first experiments found that the achiral LCLCs, sunset yellow FCF (SSY) and disodium cromoglycate (DSCG) both exhibit spontaneous mirror symmetry breaking in the nematic phase driven by a giant elastic anisotropy of their twist modulus compared to their splay and bend moduli. Resulting structures of the confined LCLCs display interesting director configurations due to interplay of topologically required defects and twisted director fields. At higher concentrations, the LCLC compounds form columnar phases. We studied the columnar phase confined within spherical drops and discovered and understood configurations of the LC that sometimes led to non-spherical droplet shapes. The second experiments with SSY LCLCs confined in hollow cylinders uncovered director configurations which were driven in large measure by an exotic elastic modulus known as saddle-splay. We measured this saddle-splay modulus in a LCLC for the first time and found it to be more than 50 times greater than the twist elastic modulus. This large relative value of the saddle-splay modulus violates a theoretical result/assumption known as the Ericksen inequality. A third group of experiments on LCLCs explored the drying process of sessile drops containing SSY solutions, including evaporation dynamics, morphology, and deposition patterns. These drops differ from typical, well-studied evaporating colloidal drops primarily due to the LCLC's concentration-dependent isotropic, nematic, and columnar phases. Phase separation occurs during evaporation, creating surface tension gradients and significant density and viscosity variation within the droplet. Thus, the drying multiphase drops exhibit new convective currents, drop morphologies, deposition patterns, as well as a novel ordered crystalline phase.Finally, experiments in colloidal glasses and super-cooled liquids were initiated to probe the relationship between structure and dynamics in their constituent particles. The displacements of individual particles in the colloids can be decomposed into small cage fluctuations and large rearrangements into new cages. We found a correlation between the rate of rearrangement and the local cage structure associated with each particle. Particle trajectories of a two-dimensional binary mixture of soft colloids are captured by video microscopy. We use a machine learning method to calculate particle "softness," which indicates the likelihood of rearrangement based on many radial structural features for each particle. We measured the residence time between consecutive rearrangements and related probability distribution functions (PDFs). The softness-dependent conditional PDF is well fit by an exponential with decay time decreasing monotonically with increasing softness. Using these data and a simple thermal activation model, we determined activation energies for rearrangements.
Download or read book Lyotropic Liquid Crystals written by Ingo Dierking and published by Oxford University Press. This book was released on 2024-07-16 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to review the field of lyotropic liquid crystals from amphiphilic to colloidal systems, bridging the gap between the two worlds of lyotropics and thermotropics by showing that many of the features observed in standard thermotropic liquid crystals may also be observed in lyotropic systems and vice versa. Indeed, for a long time, lyotropic liquid crystals have been overshadowed by their thermotropic counterparts, mainly due to the potential for application of the latter in the display industry. This picture has somewhat shifted over the last decade, with numerous novel lyotropic systems having been discovered and formulated, bringing to light their importance in wider scientific research. For example, the understanding of viruses forming self-assembled ordered phases has largely increased as mineral liquid crystals and clays have experienced a renaissance leading to fundamental research and work on structure formation in nanotechnology. Similarly, nano-rods, nano-wires, nanotubes and 2D materials like graphene oxide and others have been shown to exhibit liquid crystalline behaviour, which may be exploited in self-assembly, drug delivery or biosensors. Cellulose nanocrystals have become an important and popular field of research. The self-assembly of short chain DNA fragments has led to liquid crystal behaviour previously thought to be impossible. Chromonics were shown to exhibit fascinating physical properties, and the combination of active fluids with liquid crystals has opened a whole new field of research to be explored - 'living liquid crystals'.
Download or read book Lyotropic Chromonic Liquid Crystals written by Shuang Zhou and published by Springer. This book was released on 2017-02-14 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes lyotropic chromonic liquid crystals (LCLCs) with exotic elastic and viscous properties. The first part of the thesis presents a thorough analysis of the elastic and viscous properties of LCLCs as functions of concentration, temperature and ionic contents, while the second part explores an active nematic system: living liquid crystals, which represent a combination of LCLC and living bacteria. LCLCs are an emerging class of liquid crystals that have shown profound connections to biological systems in two aspects. First, the assembly process of the chromonic aggregates is essentially the same as DNA oligomers and other super-molecular assemblies of biological origin. LCLCs thus provide an excellent model system for studying physical properties such as the elasticity and viscosity of these supramolecular assemblies. Second, LCLCs are biocompatible, thus serving as a unique anisotropic matrix to interface with living systems such as bacteria. This thesis deepens our understanding of both aspects. The noncovalent nature of chromonic aggregation produces the unique viscoelasticity to be found in LCLCs, which differs dramatically from that of traditional LCs. Anisotropic interactions between LCLCs and bacteria lead to fascinating phenomena such as the deformation of LCLCs with a characteristic wavelength determined by the elasticity of the LCLCs and the activity of the bacteria, orientationally controlled trajectories of bacteria and visualization of 24 nm flagella motion.
Download or read book Physics And Chemistry Of Molecular Assemblies written by Kazuchika Ohta and published by World Scientific. This book was released on 2020-03-17 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: The JLCS Excellent Book Award 2021 by Japanese Liquid Crystal SocietyIn nature, a number of molecules self-assemble to form various aggregation states. In these aggregation states, numerous functions, which have never been observed in one molecule, are developed. Even for the same compound, the different aggregation states exhibit totally different physical properties in density, hardness, optical and electrical properties, medicinal effect, etc. For pursuing the functionality of materials, it may be indispensable to understand the molecular aggregation states of crystals, liquid crystals, glass, colloids, etc. In this book, the author will focus on the basis of polymorphic phenomena of crystals and liquid crystals and their physical properties. After reading this book, you will be able to change your viewpoint of matter from traditional limited 'three states of matter' to novel 'numerous states of matter.'
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 Elasticity Theory And Topological Defects In Nematic Liquid Crystals written by Cheng Long and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystal is a state of matter where constituents show orientational order, despite lack of translational order. For regular nematic liquid crystals, the ground state of orientational distribution of mesogens is described by a single axis, known as the director. Due to effects such as surface anchoring or chiral nature of added liquid crystal molecules, the uniformity in an orientational order field can be broken. The short-range spatial correlation persisting in the orientational order field, as well as topological defects enabled by the uniaxial symmetry manifested from the local orientational order of a nematic liquid crystal, often gives rise to abundant intriguing and sophisticated pattern formation in nematic liquid crystals. Studying the pattern formation and the topological defects in those orientational order fields is essential for understanding rheological and optical properties of nematic liquid crystals. Employing analytical and numerical tools, this dissertation explores the implications of elasticity theory which is commonly used to characterize the deformation of a uniform orientational order field, and the motion of different topological defects in nematic liquid crystals. In the conventional Oseen-Frank elasticity theory, a uniform ground state is protected by the elastic constants satisfying Ericksen inequalities. To examine the scope of the elasticity theory beyond the Ericksen inequalities, we revisit the Oseen-Frank elasticity theory for nematic liquid crystals from the perspective of a reformulated form and find a new set of necessary inequalities for Frank elastic constants to ensure the existence of stable solutions, which is weaker than the Ericksen inequalities. We therefore identify a regime where the Ericksen inequalities are violated but the system is still stable. Remarkably, lyotropic chromonic liquid crystals are in that regime. We investigate the nonuniform structure of the director field in that regime, show that it depends sensitively on system geometry, and discuss the implications for lyotropic chromonic liquid crystals. Applying the same reformulated elasticity theory, we prove that geometric frustration exists in cholesteric liquid crystals. We explicitly demonstrate influences of geometric frustration in two models. First, we consider a chiral liquid crystal confined in a long cylinder with free boundaries. When the radius of the tube is sufficiently small, the director field forms a double-twist configuration, which is the ideal local structure. However, when the radius becomes large enough, due to the geometric frustration, the director field transforms into either a cholesteric phase with single twist, or a set of double-twist regions separated by disclinations, depending on the ratio of disclination energy density to elastic energy density. Second, we study a cholesteric liquid crystal confined between two infinite parallel plates with free boundaries, and we find that geometric frustration induces buckled helical cholesteric structure close to the free boundaries, reminiscent of the Helfrich-Hurault instability. Inspired by the experimental observation that skyrmions in cholesteric liquid crystals can move like particles under applied electric fields, we propose a general theoretical methodology for studying the motion of localized topological objects in liquid crystals, based on collective coordinate method. In our method, the continuum field of a topological soliton is represented by a few macroscopic degrees of freedom, including the position of the excitation and the orientation of the background field, and the motion of the topological soliton is thus derived from the equations of motion for those macroscopic degrees of freedom. Using the coarse-grained method, we elucidate the mechanism of moving solitons and skyrmions in a toggling field. Finally, to understand disclinations, an important class of topological defects in liquid crystals, we build a simple nematic order tensor model for a disclination in a nematic liquid crystal clarifying an analytical relation between the properties of the tensor field close to a disclination and the rotation axis of the nematic orientation around the disclination, which turns out to be an important quantity for the behaviors of a disclination. Analogous to a dislocation in a solid, we find that a Peach-Koehler force can be induced to drive a disclination to move by applying an effective external stress, and that the force is closely related to the rotation axis of the nematic orientation. With the help of the Peach-Koehler force, we further develop a theoretical model for explaining the Frank- Read mechanism in nematic liquid crystals, where a pinned disclination can be multiplied under an effective external stress.
Download or read book Self assembly of Lyotropic Chromonic Liquid Crystals written by Heung-Shik Park and published by . This book was released on 2010 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lyotropic chromonic liquid crystals (LCLCs) are composed of plank-like molecules with rigid polyaromatic cores and two or more ionic groups at the periphery. These molecules typically stack on top of each other leaving the ionic solubilizing groups at the aggregate-water interface. As the concentration of LCLC increases, the aggregates multiply, elongate, and align parallel to each other and then form mesophases. The two most commonly met phases in LCLCs are the uniaxial nematic phase and the columnar phase with aggregates forming a hexagonal lattice in the plane perpendicular to the average orientation of aggregates. This thesis explores how the aggregate structure and the phase diagrams of LCLCs in water depend on their concentration, temperature, pH of the solution, and the presence of various additives, such as salts and neutral polymers. The two main mechanisms associated with the role of additives are (a) electrostatic interactions within and between the aggregates and (b) excluded volume effects induced by the neutral additives. Mono- or divalent salts enhance the stability of the N phase when the concentration of LCLCs and salts is small, while they suppress the mesophases when the concentration of LCLCs and salts is large. The addition of non-ionic additives such as PEG to the SSY solution leads to phase-separation into a condensed liquid crystalline (LC) region with a high concentration of SSY and a PEG-rich isotropic region. In the condensed LC region, the distance between the SSY aggregates decreases and the average length of the aggregates increases when the concentration of PEG increases. This dissertation also describes a potential application of LCLCs as a functional material for nanofabrication, namely, a controlled and reversible assembly of gold nanorods. The anisotropic electrostatic interaction between the metallic NRs and chromonic stacks allows one to achieve either side-by-side or end-to-end assembly, depending on the surface charge of the NRs. The assembly of NRs can be controlled by a number of factors influencing the self-assembly of chromonic materials, such as the concentration and pH of the solution. We hope that these studies provide a basic understanding of phase behavior and the physical properties of the reversible self-assembled chromonic materials and expand the opportunities for practical applications of LCLCs.
Download or read book Liquid Crystals Beyond Displays written by Quan Li and published by John Wiley & Sons. This book was released on 2012-05-29 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemistry, physics, and applications of liquid crystals beyond LCDs Liquid Crystals (LCs) combine order and mobility on a molecular and supramolecular level. But while these remarkable states of matter are most commonly associated with visual display technologies, they have important applications for a variety of other fields as well. Liquid Crystals Beyond Displays: Chemistry, Physics, and Applications considers these, bringing together cutting-edge research from some of the most promising areas of LC science. Featuring contributions from respected researchers from around the globe, this edited volume emphasizes the chemistry, physics, and applications of LCs in areas such as photovoltaics, light-emitting diodes, filed-effect transistors, lasers, molecular motors, nanophotonics and biosensors. Specific chapters look at magnetic LCs, lyotropic chromonic LCs, LC-based chemical sensors, LCs in metamaterials, and much more. Introducing readers to the fundamentals of LC science through the use of illustrative examples, Liquid Crystals Beyond Displays covers not only the most recent research in the myriad areas in which LCs are being utilized, but also looks ahead, addressing potential future developments. Designed for physicists, chemists, engineers, and biologists working in academia or industry, as well as graduate students specializing in LC technology, this is the first book to consider LC applications across a wide range of fields.
Download or read book Encyclopedia of Colloid and Interface Science written by Tharwat Tadros and published by Springer. This book was released on 2013-06-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An authoritative and comprehensive reference relevant to all scientists and engineers in the field. This encyclopedia not only helps chemistry, materials science and physics researchers to understand the principles, but also provides practicing engineers with the necessary information for implementing practical applications, such as Food and agrochemicals Polymers and ceramics Cosmetics and detergents Paints and coatings Pharmaceuticals and drug delivery In addition, the encyclopedia is an important reference for industrial chemists and chemical engineers faced with a multitude of industrial systems of a colloidal nature. As wide as the range of applications that colloid and interface science has is the range of scientific disciplines that contribute to research and development in this field. These encompass chemistry, physics, biology and mathematics as well as nanoscience and nanotechnology. The encyclopedia provides easy-to-digest information for meeting these interdisciplinary challenges. While providing numerous concise definitions of key terms, the encyclopedia also features more than forty in-depth essays on topics ranging from Agrochemical Formulations to Zeta Potential. All entries are cross-referenced and include selected references to original literature as well as synonyms.
Download or read book Soft Matter Physics written by Maurice Kleman and published by Springer Science & Business Media. This book was released on 2007-05-28 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of "soft matter" materials with complex properties has raised a number of interesting problems in basic physics, biology, and materials science, all of which promise new and important technological applications. After a review of chemical bonds and phase transitions, the authors treat topics such as surface phenomena, stability of colloidal systems, structural properties of polymers, and topological defects. The monograph's emphasis on underlying physical principles offers a coherent treatment of the great variety of research in the field.
Download or read book New Trends in Lyotropic Liquid Crystals written by Ingo Dierking and published by MDPI. This book was released on 2020-11-02 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystals (LCs) were discovered more than a century ago, and were, for a long time, treated as a physical curiosity, until the development of flat panel screens and display devices caused a revolution in the information display industry, and in fact in society. There would be no mobile phones without liquid crystals, no flat screen TVs or computer monitors, no virtual reality, just to name a few of the applications that have changed our whole world of vision and perception. All of these inventions are based on liquid crystals that are formed through a change in temperature, thermotropic LCs. However, there is another form of liquid crystals, described even earlier, yet much less talked about; the lyotropic liquid crystals that occur through the change of concentration of some molecules in a solvent. These are found in abundance in nature, making up the cell membranes, and are used extensively in the food, detergents and cosmetics industries. In this collection of articles by experts in their respective research areas, we bring together some of the most recent and innovative aspects of lyotropic liquid crystals, which we believe will drive future research and set novel trends in this field.
Download or read book Concentrated Dispersions written by American Chemical Society. Division of Colloid and Surface Chemistry and published by . This book was released on 2004 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume covers many aspects concerning the preparation, characterization, stabilization, and behavior of concentrated colloidal dispersion and presents the most recent advances in experimental techniques and theoretical methods for studying concentrated colloidal dispersions.
Download or read book Defects in Liquid Crystals Computer Simulations Theory and Experiments written by Oleg D. Lavrentovich and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Topological defects are the subject of intensive studies in many different branches of physics ranging from cosmology to liquid crystals and from elementary particles to colloids and biological systems. Liquid crystals are fascinating materials which present a great variety of these mathematical objects and can therefore be considered as an extremely useful laboratory for topological defects. This book is the first attempt to present together complementary approaches to the investigations of topological defects in liquid crystals using theory, experiments and computer simulations.
Download or read book Liquid Crystal Colloids written by Igor Muševič and published by Springer. This book was released on 2017-05-14 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together the many concepts and discoveries in liquid crystal colloids contributed over the last twenty years and scattered across numerous articles and book chapters. It provides both a historical overview of the development of the field and a clear perspective on the future applications in photonics. The book covers all phenomena observed in liquid crystal colloids with an emphasis on experimental tools and applications of topology in condensed matter, as well as practical micro-photonics applications. It includes a number of spectacular manifestations of new topological phenomena not found or difficult to observe in other systems. Starting from the early works on nematic colloids, it explains the basics of topological defects in ordered media, charge and winding, and the elastic forces between colloidal particles in nematics. Following a detailed description of experimental methods, such as optical tweezing and particle tracking, the book eases the reader into the theoretical part, which deals with elastic deformation of nematic liquid crystals due to inclusions and surface alignment. This is discussed in the context of basic mean field Landau-de Gennes Q-tensor theory, with a brief explanation of the free-energy minimization numerical methods. There then follows an excursion into the topology of complex nematic colloidal structures, colloidal entanglement, knotting and linking. Nematic droplets, shells, handlebodies and chiral topological structures are addressed in separate chapters. The book concludes with an extensive chapter on the photonic properties of nematic dispersions, presenting the concept of integrated soft matter photonics and discussing the concepts of nematic and chiral nematic microlasers, surface-sensitive photonic devices and smectic microfibers. The text is complemented by a large bibliography, explanatory sketches and beautiful micrographs.
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 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 Handbook of Materials Modeling written by Sidney Yip and published by Springer Science & Business Media. This book was released on 2007-11-17 with total page 2903 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first reference of its kind in the rapidly emerging field of computational approachs to materials research, this is a compendium of perspective-providing and topical articles written to inform students and non-specialists of the current status and capabilities of modelling and simulation. From the standpoint of methodology, the development follows a multiscale approach with emphasis on electronic-structure, atomistic, and mesoscale methods, as well as mathematical analysis and rate processes. Basic models are treated across traditional disciplines, not only in the discussion of methods but also in chapters on crystal defects, microstructure, fluids, polymers and soft matter. Written by authors who are actively participating in the current development, this collection of 150 articles has the breadth and depth to be a major contributor toward defining the field of computational materials. In addition, there are 40 commentaries by highly respected researchers, presenting various views that should interest the future generations of the community. Subject Editors: Martin Bazant, MIT; Bruce Boghosian, Tufts University; Richard Catlow, Royal Institution; Long-Qing Chen, Pennsylvania State University; William Curtin, Brown University; Tomas Diaz de la Rubia, Lawrence Livermore National Laboratory; Nicolas Hadjiconstantinou, MIT; Mark F. Horstemeyer, Mississippi State University; Efthimios Kaxiras, Harvard University; L. Mahadevan, Harvard University; Dimitrios Maroudas, University of Massachusetts; Nicola Marzari, MIT; Horia Metiu, University of California Santa Barbara; Gregory C. Rutledge, MIT; David J. Srolovitz, Princeton University; Bernhardt L. Trout, MIT; Dieter Wolf, Argonne National Laboratory.
