Download or read book Fluid Flow in Freely Suspended Smectic Liquid Crystal Films written by Maxwell I. Godfrey and published by . This book was released on 1995 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure and Dynamics of Freely Suspended Liquid Crystals written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Smectic liquid crystals are phases of rod shaped molecules organized into one dimensionally (1 D) periodic arrays of layers, each layer being between one and two molecular lengths thick. In the least ordered smectic phases, the smectics A and C, each layer is a two dimensional (2D) liquid. Additionally there are a variety of more ordered smectic phases having hexatic short range translational order or 2D crystalline or quasi long range translational order within the layers. The inherent fluid-layer structure and low vapor pressure of smectic liquid crystals enables the long term stabilization of freely suspended, single component, layered fluid films as thin as 30A, a single molecular layer. The layering forces the films to be an integral number of smectic layers thick, quantizing their thickness in layer units and forcing a film of a particular number of layers to be physically homogeneous with respect to its layer structure over its entire area. Optical reflectivity enables the precise determination of the number of layers. These ultrathin freely suspended liquid crystal films are structures of fundamental interest in condensed matter and fluid physics. They are the thinnest known stable fluid structures and have the largest surface-to-volume ratio of any stable fluid preparation, making them ideal for the study of the effects of reduced dimensionality on phase behavior and on fluctuation and interface phenomena. Their low vapor pressure and quantized thickness enable the effective use of microgravity to extend the study of basic capillary phenomena to ultrathin fluid films. Freely suspended films have been a wellspring of new LC physics. They have been used to provide unique experimental conditions for the study of condensed phase transitions in two dimensions. They are the only system in which the hexatic has been unambiguously identified as a phase of matter, and the only physical system in which fluctuations of a 2D XY system and Kosterlitz Thouless phase tran
Download or read book Structure Hydrodynamics and Phase Transition of Freely Suspended Liquid Crystals written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Smectic liquid crystals are phases of rod shaped molecules organized into one dimensionally (1D) periodic arrays of layers, each layer being between one and two molecular lengths thick. In the least ordered smectic phases, the smectics A and C, each layer is a two dimensional (2D) liquid. Additionally there are a variety of more ordered smectic phases having hexatic short range translational order or 2D crystalline quasi long range translational order within the layers. The inherent fluid-layer structure and low vapor pressure of smectic liquid crystals enable the long term stabilization of freely suspended, single component, layered fluid films as thin as 30A, a single molecular layer. The layering forces the films to be an integral number of smectic layers thick, quantizing their thickness in layer units and forcing a film of a particular number of layers to be physically homogeneous with respect to its layer structure over its entire area. Optical reflectivity enables the precise determination of the number of layers. These ultrathin freely suspended liquid crystal films are structures of fundamental interest in condensed matter and fluid physics. They are the thinnest known stable condensed phase fluid structures and have the largest surface-to-volume ratio of any stable fluid preparation, making them ideal for the study of the effects of reduced dimensionality on phase behavior and on fluctuation and interface phenomena. Their low vapor pressure and quantized thickness enable the effective use of microgravity to extend the study of basic capillary phenomena to ultrathin fluid films. Freely suspended films have been a wellspring of new liquid crystal physics. They have been used to provide unique experimental conditions for the study of condensed phase transitions in two dimensions. They are the only system in which the hexatic has been unambiguously identified as a phase of matter, and the only physical system in which fluctuations of a 2D XY system and Kosterl
Download or read book Dynamics of Topological Defects in Freely Floating Smectic Liquid Crystal Films and Bubbles written by Amine Missaoui and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure Formation and Dynamics in Molecularly Thin Smectic Liquid Crystal Films written by Benjamin Schulz and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This doctoral thesis presents a study of thin films of smectic liquid crystals. This class of material shows the property to form stable films of only a few molecules thickness both on substrates and freely suspended in air. This feature together with the anisotropy of the material offers the possibility to prepare and investigate samples that cannot be formed by other materials. As the dimensions of the films are reduced, the physical properties are expected to change with respect to the observed surface structures and the dynamics in the film. For freely suspended films, the presented wor ...
Download or read book Dynamic Light Scattering Studies of Layer Fluctuations in Freely Suspended Smectic Liquid Crystal Films written by Sunil K. Sharma and published by . This book was released on 2007 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Smectic liquid crystalline films or membranes have been widely studied by using the hydrodynamic theory and dynamical scattering methods, but most studies have been confined to either frequency domain light scattering measurements above ~1GHz, which probe sound waves in a limit where damping is a weak effect, or by low frequency photon correlation spectroscopy, performed in the time domain below 10 MHz (i.e., for times) and usually designed to study overdamped fluctuations of the smectic layer orientation when inertia is negligible. The interesting crossover regime, where inertia, damping, and elastic forces all contribute significantly in the hydrodynamic description, has posed a long standing challenge to scattering experiments. In this dissertation we present an extension of the optical photon correlation spectroscopy (PCS) technique down to ~100 picosecond resolution that fully closes the historical gap between frequency and time domain scattering techniques. We study smectic films from which we can determine, for optical wavevectors 10^4-10^5/cm, both the propagation frequency and damping rate for undulatory motion of thin free standing smectic films (a few tens of molecular layers), as well as the relaxation rates associated with overdamped layer dynamics of bulk films (thousands of layers thick), by measuring the time correlation function of the intensity of light scattered from thermal motion of the film surfaces. We find that the standard hydrodynamic model for incompressible, isothermal smectic films provides a good overall framework for quantitative analysis of our correlation data in both under and overdamped regimes for films of common cyanobiphenyl liquid crystals in the SmA phase. In particular, the main elastic properties - the film surface tension and compression elastic constant - are found to be reasonably consistent with values obtained from other, more invasive techniques. However, there are significant aspects in which the standard model appears incomplete. First, in relatively thin films where the dominant scattering comes from nearly pure undulation modes of the film, the effective layer sliding viscosity is more than an order of magnitude less than values reported in bulk samples, typically measured between substrates. On the other hand, in a very thick film, we obtain a result, from purely overdamped dynamics, which basically agrees with quoted bulk values of the layer viscosity. Second, in thinner films, we detect an additional, overdamped mode not expected in the light scattering derived from the standard hydrodynamic theory. We propose that this mode is associated with consequences of a higher degree of order on the film surfaces. We have also carried out preliminary surface light scattering experiments on layer motion in thin smectic-C and hexatic-B films. The dynamical parameters obtained from fits to these data show only modest variations through the SmA-SmC and SmA-HexB transitions. The additional, overdamped mode is revealed to be clearly hydrodynamic (relaxation rate ~ square of wavevector) over the range probed.
Download or read book Freely Suspended Liquid Crystalline Films written by A. A. Sonin and published by John Wiley & Sons. This book was released on 1998 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Freely Suspended Liquid Crystalline Films Andrei A. Sonin Centre d'Etudes Atomiques de Saclay, France and Institute of Crystallography, Russian Academy of Sciences with a Foreword by Professor Noel Clark University of Colorado, USA This book provides a brief introduction to the physics of liquid crystals and to macroscopic physical parameters characterising freely suspended liquid crystalline (FSLC) films, and then reviews the experimental techniques for preparing these films, measuring their thicknesses, and investigating their physical properties and structural aspects. Molecular structures and defects of FSLC films and the problems of film stability, thinning and rupture are discussed in later chapters. Physical phenomena, such as orientational and phase transitions, Frederick's and flexoelectric effects, hydroelectrodynamics, etc., are also analysed. Finally, some applications of FSLC films in industry and in various branches of science are discussed. Specialists working in the physics of liquid crystals and in surface physics will find this book of interest. Industrial firms and their research centres investigating liquid crystals, biological membranes, detergent/surfactant/biomedical areas; and graduates and postgraduates in solid state physics and crystallography will also benefit from this book. The book has an easy-to-read style with just the minimum amount of mathematics necessary to explain important concepts. This is the first book dedicated exclusively to the physics of FSLC in almost a century since their discovery and last twenty years of their active studies. Andrei Sonin, a scientist in the area of FSLC and author of many articles on surface phenomena in liquid crystals, the properties and behaviour of thin liquid crystalline and surfactant films, has a long standing reputation in liquid crystals and surfactant systems and has been particularly active in issues involving surface interactions.
Download or read book Liquid Crystals With Nano And Microparticles In 2 Volumes written by Jan P F Lagerwall and published by World Scientific. This book was released on 2016-10-10 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'The overall book content is excellently coordinated to form a synchronised story, interesting to a broad scientific audience … The book summarises the present knowledge in the field, introduces fundamental concepts to the beginners, describes key measuring methods and presents several different typical demonstrative systems, some of them exhibiting an extraordinary rich spectrum of structures and superstructures. I am sure that with time the book will become an attractor to a broad audience (physicists, chemists, material scientists, engineers, etc.), ranging from students, beginners in the field to experienced researchers. To summarise, this is the book that I have been missing on my bookshelf.'Liquid Crystals TodayWhile liquid crystals are today widely known for their successful application in flat panel displays (LCDs), academic liquid crystal research is more and more targeting situations where these anisotropic fluids are put to completely different use, in varying contexts. A particularly strong focus is on colloidal liquid crystals, where particles, bubbles or drops are dispersed in a liquid crystal phase. The liquid crystal can act as a host phase, with the inclusions constituting foreign guests that disturb the local order in interesting ways, often resulting in large-scale positional arrangement and/or uniform alignment of the guests. But it may also be formed by solid particles themselves, if these are of nanoscale dimensions and of disc- or rod-shape, and if they are suspended in an isotropic liquid host at sufficient concentration.This book aims to cover both the modern research tracks, gathering pioneering researchers of the different subfields to give a concise overview of the basis as well as the prospects of their respective specialties. The scope spans from curiosity-driven fundamental scientific research to applied sciences. Over the course of the next decade, the former is likely to generate new tracks of the latter type, considering the exploratory and productive phase of this young research field.
Download or read book Solitons in Liquid Crystals written by Lui Lam and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solitons are a well-known and intriguing aspect of nonlinear behavior in a continuous system such as a fluid: a wave propagates through the medium without distortion. Liquid crystals are highly ordered systems without a rigid, long-range structure. Solitons in liquid crystals (sometimes referred to as "walls") have a wide variety of remarkable properties that are becoming important for practical applications such as electroluminescent display. This book, the first review of the subject to be published, contains not only surveys of the existing literature, but presents new results as well.
Download or read book Symmetry and Structure of Freely Suspended Liquid Crystal Films written by Darren R. Link and published by . This book was released on 1998 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Studies of Liquid Crystal Films written by Hui Hsiung and published by . This book was released on 1986 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Liquid Crystal Structure Using Freely Suspended Films written by Nattaporn Chattham and published by . This book was released on 2004 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Topological Soft Matter written by Francesca Serra and published by Frontiers Media SA. This book was released on 2020-12-02 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.
Download or read book Fluctuational Effects in the Dynamics of Liquid Crystals written by E.I. Kats and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystals, widely used in displays for electronic equipment and other applications, have highly unusual properties arising from the anisotropy of their molecules. It appears that some aspects of the fluid dynamics of liquid crystals, such as their viscosity, can be understood only by considering the role played by thermal fluctuations. In order to provide a theoretical framework for understanding the experimental results, the authors devote a large part of the book to a derivation of the nonlinear dynamic equations and to a discussion of linearized equations for the various types of liquid crystals. The diagrammatic and other techniques they use are of general use in condensed matter physics, and this exposition should thus be of interest to all condensed-matter theorists.
Download or read book Liquid Crystals From Modified Phases to Applications 2014 written by João Luis Maia Figueirinhas and published by MDPI. This book was released on 2018-10-08 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Liquid Crystals" that was published in Materials
Download or read book Liquid Crystals written by Sergey V. Pasechnik and published by John Wiley & Sons. This book was released on 2009-09-18 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering numerous practical applications as yet not covered in any single source of information, this monograph discusses the importance of viscous and elastic properties for applications in both display and non-display technologies. The very well-known authors are major players in this field of research and pay special attention here to the use of liquid crystals in fiber optic devices as applied in telecommunication circuits.
Download or read book Pattern Formation in Liquid Crystals written by Agnes Buka and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 20 years the study of nonlinear nonequilibrium phenomena in spa tially extended systems, with particular emphasis on pattern-forming phenomena, has been one of the very active areas in physics, exhibiting interesting ramifi cations into other sciences. During this time the study of the "classic" systems, like Rayleigh-Benard convection and Taylor vortex flow in simple fluids, has also been supplemented by the study of more complex systems. Here liquid crystals have played, and are still playing, a major role. One might say that liquid crystals provide just the right amount and right kind of complexity. They are full of non linearities and give rise to new symmetry classes, which are sometimes actually simpler to deal with qualitatively, but they still allow a quantitative description of experiments in many cases. In fact one of the attractions of the field is the close contact between experimentalists and theorists. Hydrodynamic instabilities in liquid crystals had already experienced a period of intense study in the late 1960s and early 1970s, but at that time neither the ex perimental and theoretical tools nor the concepts had been developed sufficiently far to address the questions that have since been found to be of particular interest. The renewed interest is also evidenced by the fact that a new series of workshops has evolved. The first one took place in 1989 in Bayreuth and united participants from almost all groups working in pattern formation in liquid crystals.
