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 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 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 Studies on Lyotropic Chromonic Liquid Crystals in Nematic and Biphasic Regions written by Xuxia Yao and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chromonic liquid crystals are a relatively new class of lyotropic liquid crystals. In an effort to understand this lyotropic phase better, studies on the phase behavior, defects formed in these systems and characterization of the order were performed. We studied three chromonic liquid crystal materials in nematic and biphasic regions: Sunset Yellow FCF (SSY, a food dye), a cationic perylene diimide derivative (PDI, a conducting dye) and cromolyn sodium (DSCG, a drug). For SSY chromonics in the nematic region, order parameters (and) were obtained by polarized Raman measurements. Using the order parameters the flow behavior was predicted and was found to be non-flow aligning. A comprehensive viscoelastic property set of SSY chromonics was obtained by studying the statics and dynamics of defects during the formation of planar aligned monodomain. Applications of PDI thin films as vapor sensors were explored; anisotropic electronic properties of oriented PDI films show good conductivity along the columns presumably arising from the overlap between the? systems. In the biphasic region, growth and fluctuation of SSY tactoids and interesting patterns of biphasic DSCG under capillary geometry were observed; elastic properties and surface tension were estimated based on the shape of DSCG tactoids. Polymer dispersed lyotropic chromonic liquid crystals with different drop shapes and director configurations were also fabricated using various water-soluble polymers.
Download or read book Nanostructuring Lyotropic Chromonic Liquid Crystals written by Tod L. Schneider and published by . This book was released on 2005 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Liquid Crystals written by Peter J. Collings and published by CRC Press. This book was released on 2019-10-23 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to Liquid Crystals: Chemistry and Physics, Second Edition relies on only introductory level chemistry and physics as the foundation for understanding liquid crystal science. Liquid crystals combine the material properties of solids with the flow properties of fluids. As such they have provided the foundation for a revolution in low-power, flat-panel display technology (LCDs). In this book, the essential elements of liquid crystal science are introduced and explained from the perspectives of both the chemist and physicist. This new edition relies on only introductory level physics and chemistry as the foundation for understanding liquid crystal science and is, therefore, ideal for students and recent graduates. Features Introduces and explains the essential elements of liquid crystal science, including discussion of how liquid crystals have been utilized for innovative and important applications. New to this edition are over 300 figures, 90 end-of chapter exercises, and an increased scope that includes recent developments. Combines the knowledge of two eminent scientists in the field; they have fully updated and expanded the text to cover undergraduate/graduate course work as well as current research in what is now a billion-dollar industry. Immerses the reader in the vocabulary, structures, data, and kinetic models, rapidly building up an understanding of the theories and models in current use. Begins with a historical account of the discovery of liquid crystals and continues with a description of how different phases are generated and how different molecular architectures affect liquid crystal properties.
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 Fluids Colloids and Soft Materials written by Alberto Fernandez-Nieves and published by John Wiley & Sons. This book was released on 2016-05-09 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a compilation of self-contained chapters covering a wide range of topics within the broad field of soft condensed matter. Each chapter starts with basic definitions to bring the reader up-to-date on the topic at hand, describing how to use fluid flows to generate soft materials of high value either for applications or for basic research. Coverage includes topics related to colloidal suspensions and soft materials and how they differ in behavior, along with a roadmap for researchers on how to use soft materials to study relevant physics questions related to geometrical frustration.
Download or read book Optical Characterization of Lyotropic Chromonic Liquid Crystals written by Hui Liu and published by . This book was released on 2006 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lyotropic chromonic liquid crystals (LCLCs) represent a special class of lyotropic mesophases markedly different from conventional amphiphilic mesogens. Materials forming LCLCs are composed of plank-like molecules with a polyaromatic central core and hydrophilic ionic groups at the periphery. The individual molecules tend to assemble into rodlike aggregates that form the N phase once the concentration exceeds about 0.1M. The LCLC materials show a tremendous potential for applications in optics as self-assembling polarizing and compensating films and in the area of real-time biological sensing. The emerging applications require an understanding of basic properties of LCLC. This work addresses these needs by providing the optical characterization of LCLC. We studied in detail the optical anisotropic properties of three different nematic LCLCs: disodium cromoglycate (DSCG), blue 27, and violet 20. We determined the birefringence of these three materials as the function of the temperature T and wavelength fÜ and the corresponding dependencies of the absorption coefficients for blue 27 and violet 20. The birefringence is negative and significantly lower in the absolute value as compared to the birefringence of typical thermotropic N materials. We determined the scalar order parameter of the nematic phase of blue 27 and its temperature dependence. The scalar order parameter is close to the one predicted by the classic Onsager theory for solutions of rigid rods. However, this similarity is not complete, as the measured scalar order parameter depends on temperature. The I-N pretransitional fluctuations in an aqueous solution of DSCG were studied by light scattering. We obtained the correlation length of the orientational order-parameter fluctuations of isotropic DSCG solution. The pretransitional behavior of light scattering does not completely follow the classic Landau-de Gennes model. This feature is explained by the variable length of DSCG aggregates as a function of temperature.
Download or read book Liquid Crystals written by Pawel Pieranski and published by John Wiley & Sons. This book was released on 2021-08-31 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book on liquid crystals reports on the new perspectives that have been brought about by the recent expansion of frontiers and overhaul of common beliefs. First, it explores the interaction of light with mesophases, when the light or matter is endowed with topological defects. It goes on to show how electrophoresis, electro-osmosis and the swimming of flagellated bacteria are affected by the anisotropic properties of liquid crystals. It also reports on the recent progress in the understanding of thermomechanical and thermohydrodynamical effects in cholesterics and deformed nematics and refutes the common belief that these effects could explain Lehmann’s observations of the rotation of cholesteric droplets subjected to a temperature gradient. It then studies the physics of the dowser texture, which has remarkable properties. This is of particular interest in regards to nematic monopoles, which can easily be generated, set into motion and collided within it. Finally, this book deals with the spontaneous emergence of chirality in nematics made of achiral molecules, and provides a brief historical context of chirality
Download or read book Chiral Lyotropic Chromonic Liquid Crystals Composed of Disodium Cromoglycate Doped with Water soluble Chiral Additives1 written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Crystals That Flow written by Timothy J. Sluckin and published by Springer Science & Business. This book was released on 2004-06 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: The collection is divided into sections, each of which is prefaced by a brief commentary referring to the historic-scientific context of the time.
Download or read book Metallomesogens written by Jose Luis Serrano and published by John Wiley & Sons. This book was released on 2008-09-26 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on metal-containing liquid crystals is a rapidly expanding, multidisciplinary field with new materials continually being synthesized and novel applications being developed. 'Metallomesogens' is the first comprehensive survey of the field, introducing the reader to: * materials design * synthesis * physical properties * emerging applications Carefully selected references round off this well-organized compendium. It is an indispensable guide to experienced researchers in coordination and organometallic chemistry as well as in liquid-crystal and materials science. Newcomers and graduate students will also benefit from this didactically sound introduction to the field.
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 Optical Coherence Tomography and Its Non medical Applications written by Michael Wang and published by BoD – Books on Demand. This book was released on 2020-05-27 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is a promising non-invasive non-contact 3D imaging technique that can be used to evaluate and inspect material surfaces, multilayer polymer films, fiber coils, and coatings. OCT can be used for the examination of cultural heritage objects and 3D imaging of microstructures. With subsurface 3D fingerprint imaging capability, OCT could be a valuable tool for enhancing security in biometric applications. OCT can also be used for the evaluation of fastener flushness for improving aerodynamic performance of high-speed aircraft. More and more OCT non-medical applications are emerging. In this book, we present some recent advancements in OCT technology and non-medical applications.
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.
