The Molecular Dynamics of Liquid Crystals

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 ...

Author: G.R. Luckhurst

Publisher: Springer Science & Business Media

ISBN: 9789401111683

Category: Science

Page: 610

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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.
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Discotic Liquid Crystals

This book starts with a brief overview of liquid crystals in general, and discotic liquid crystals in particular.

Author: Olga Viktorovna Kruglova

Publisher: IOS Press

ISBN: 1586037455

Category: Science

Page: 117

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" In this dissertation the dependency between structure and dynamics, and its influence on charge transfer properties of self-assembling discotic liquid crystalline materials, are studied in some detail. Dynamics was probed by quasielastic neutron scattering (protons) and PR-TRMC (charge carriers). Both techniques are complimentary since they give information about different parts of a single system and they should give the same qualitative result. This book starts with a brief overview of liquid crystals in general, and discotic liquid crystals in particular. Subsequently, a theory of neutron scattering is discussed in detail followed by description of the continuous time random walk model on which the fractional diffusion equation is built. Solution of that fractional diffusion equation represents van Hove correlation Function that is measured in neutron scattering experiment. The model for relaxation kinetics in a correlating environment parameterizes the van Hove correlation function and gives a more physical insight of the processes occurring in system. After a short description of the conduction process, the possible connection between molecular dynamics and charge carrier motion is examined. "
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Advances in Liquid Crystal Research and Applications

This volume is comprised of three parts. The first part deals with the phases and structures of liquid crystals through methods employing synthesis, X-ray studies, electron diffraction, and calorimetric determination.

Author: Lajos Bata

Publisher: Elsevier

ISBN: 9781483150178

Category: Science

Page: 704

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Advances in Liquid Crystal Research and Applications, Volume 1 is a collection of papers presented at the Third Liquid Crystal Conference of the Socialist Countries, held in Budapest on August 27-31, 1979. This volume is comprised of three parts. The first part deals with the phases and structures of liquid crystals through methods employing synthesis, X-ray studies, electron diffraction, and calorimetric determination. The second part discusses molecular dynamics and dynamical methods where mostly dielectric investigations into liquid crystal properties are emphasized. This part includes the developments in the study of molecular dynamics in liquid crystals. Other topics presented in this part are the acousto-optical and ultrasonic relaxation methods. The third part covers the continual properties of liquid crystals: their properties and behavior when exposed to different testing methods and variables. For example, a correlation between viscosity coefficients of starting components and those of their mixtures is attempted, resulting when MBBA and EBBA in different percentages are mixed, that none of their coefficients is found to obey any pronounced law. However, the viscosity coefficients given in the table may serve as reference data for further studies. Physicists; process engineers; and graduate students in physics, chemistry, and materials science fields; and university professors and lecturers related to studies in the field of liquid crystals will find this collection of papers highly informative and rewarding.
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Nuclear Magnetic Resonance of Liquid Crystals

Intended for researchers and students in physics, chemistry and materials science, this book provides the necessary background information and sufficient mathematical and physical detail to study the current research literature.

Author: Ronald Y. Dong

Publisher: Springer

ISBN: 1461273544

Category: Science

Page: 309

View: 773

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Intended for researchers and students in physics, chemistry and materials science, this book provides the necessary background information and sufficient mathematical and physical detail to study the current research literature. The book begins with a survey of liquid crystal phases and field effects, together with an introduction to the basic physics of nuclear magnetic resonance. It then discusses orientational ordering and molecular field theories for various liquid crystal molecules and nmr studies of uniaxial and biaxial phases. Subsequent chapters consider spin relaxation processes and rotational, translational, and internal molecular dynamics of liquid crystals. The final chapter discusses two-dimensional and multiple- quantum nmr spectroscopies and their application in elucidating liquid crystal properties. This second edition, updated throughout, incorporates many new references and includes new mathematical appendices.
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