A NMR Study of Molecular Motion in Liquid Crystals

A NMR Study of Molecular Motion in Liquid Crystals PDF Author: Lyndsie S. Selwyn
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Deuteron magnetic resonance spectroscopy
Languages : en
Pages : 482

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A NMR Study of Molecular Motion in Liquid Crystals

A NMR Study of Molecular Motion in Liquid Crystals PDF Author: Lyndsie S. Selwyn
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Deuteron magnetic resonance spectroscopy
Languages : en
Pages : 482

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Book Description


Nuclear Magnetic Resonance Spectroscopy of Liquid Crystals

Nuclear Magnetic Resonance Spectroscopy of Liquid Crystals PDF Author: Ronald Y. Dong
Publisher: World Scientific
ISBN: 9814273678
Category : Science
Languages : en
Pages : 462

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Book Description
This edited volume provides an extensive overview of how nuclear magnetic resonance can be an indispensable tool to investigate molecular ordering, phase structure, and dynamics in complex anisotropic phases formed by liquid crystalline materials. The chapters, written by prominent scientists in their field of expertise, provide a state-of-the-art scene of developments in liquid crystal research. The fantastic assortment of shape anisotropy in organic molecules leads to the discoveries of interesting new soft materials made at a rapid rate which not only inject impetus to address the fundamental physical and chemical phenomena, but also the potential applications in memory, sensor and display devices. The review volume also covers topics ranging from solute studies of molecules in nematics and biologically ordered fluids to theoretical approaches in treating elastic and viscous properties of liquid crystals. This volume is aimed at graduate students, novices and experts alike, and provides an excellent reference material for readers interested in the liquid crystal research. It is, indeed, a reference book for every science library to have. Sample Chapter(s). Chapter 1: Novel Strategies for Solving Highly Complex NMR Spectra of Solutes in Liquid Crystals (1,464 KB). Contents: Novel Strategies for Solving Highly Complex NMR Spectra of Solutes in Liquid Crystals (E E Burnell et al.); Analytical Potentials of Natural Abundance Deuterium NMR Spectroscopy in Achiral Thermotropics and Polypeptide Chiral Oriented Solvents (P Lesot & C Aroulande); Noble Gas Probes in NMR Studies of Liquid Crystals (J Jokisaari); Bicelles OCo A Much Needed Magic Wand to Study Membrane Proteins by NMR Spectroscopy (R Soong et al.); Advances in Proton NMR Relaxometry in Thermotropic Liquid Crystals (P J Sebastiuo et al.); Deuterium NMR Study of Magnetic Field Distortions in Ferroelectric Mesogens (R Y Dong); Deuteron NMR Study of the Effects of Random Quenched Disorder in 12CB Silica Dispersions (D Finotello & V Pandya); Dynamics of Liquid Crystals by Means of Deuterium NMR Relaxation (C A Veracini & V Domenici); Translational Self-Diffusion Measurements in Thermotropics by Means of Statistic Field Gradients NMR Diffusometry (M Cifelli); Deuterium NMR Studies of Static and Dynamic Director Alignment for Low Molar Mass Nematics (A Sugimura & G R Luckhurst); Viscoelastic Properties of Liquid Crystals: Statistical-Mechanical Approaches and Molecular Dynamics Simulations (A V Zakharov); Carbon-13 NMR Studies of Thermotropic Liquid Crystals (R Y Dong); A Combined DFT and Carbon-13 NMR Study of a Biaxial Bent-Core Mesogen (A Marini et al.). Readership: Chemists, physicists and material scientists. In particular, NMR spectroscopists.

The Molecular Dynamics of Liquid Crystals

The Molecular Dynamics of Liquid Crystals PDF Author: G.R. Luckhurst
Publisher: Springer Science & Business Media
ISBN: 9401111685
Category : Science
Languages : en
Pages : 612

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Book Description
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.

NMR of Liquid Crystal Dendrimers

NMR of Liquid Crystal Dendrimers PDF Author: Carlos Rodrigues da Cruz
Publisher: CRC Press
ISBN: 9814745731
Category : Science
Languages : en
Pages : 248

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Book Description
Dendrimers are hyperbranched molecules with well-defined nanometer-scale dimensions. Important technological applications of these systems, both in biomedicine and materials science, have been recently proposed. Liquid crystal dendrimers are fascinating materials that combine the characteristics of dendrimers with the anisotropic physical behaviour and molecular self-organization typical of liquid crystals. This unique association of physical and chemical properties, together with the possibility of multi-selective functionalization put forward by dendrimers, opens new perspectives for applications. Nuclear magnetic resonance (NMR) is a powerful experimental technique applied in materials science and an important tool to the study of molecular organization and dynamics. This book presents an introduction to dendrimers properties with special insight into liquid crystal dendrimers and a detailed description of the NMR theory and experimental techniques used in the investigation of these materials. It also discusses recent NMR research results on liquid crystal dendrimers, with emphasis on molecular order and dynamics studies. This book introduces the properties of dendrimers, with special insight into liquid crystal dendrimers, and a detailed description of NMR theory and experimental techniques used in the investigation of these materials. It also discusses results of recent NMR research on liquid crystal dendrimers, with an emphasis on molecular order and dynamics studies. Advanced undergraduate and graduate students of physics, chemistry, and materials science and researchers in the fields of dendrimers, liquid crystals, and NMR will find the book extremely useful.

Nuclear Magnetic Resonance of Liquid Crystals

Nuclear Magnetic Resonance of Liquid Crystals PDF Author: Ronald Y. Dong
Publisher: Springer Science & Business Media
ISBN: 146121954X
Category : Science
Languages : en
Pages : 320

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Book Description
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.

NMR Spectroscopy Using Liquid Crystal Solvents

NMR Spectroscopy Using Liquid Crystal Solvents PDF Author: JW Emsley
Publisher: Elsevier
ISBN: 1483279944
Category : Science
Languages : en
Pages : 385

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Book Description
NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions on internal motion studies, NMR spectra from quadpolar nuclei, and the anisotropy in nuclear spin-spin coupling. The final chapters review the theoretical and experimental studies on the anisotropy in chemical shifts, nematic rotation, and the nuclear magnetic double resonance. This book will prove useful to analytical chemists.

NMR of Ordered Liquids

NMR of Ordered Liquids PDF Author: E.E. Burnell
Publisher: Springer Science & Business Media
ISBN: 9401702217
Category : Science
Languages : en
Pages : 465

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Book Description
NMR of Ordered Liquids gives a unique overview of the scope and limitations of the NMR of oriented liquids, based on contributions from acknowledged experts in the field. The book consists of four sections: -detailed general introduction which covers the basic principles and sophisticated experimental techniques; -wide variety of applications ranging from NMR studies of small atoms and molecules in anisotropic liquids to the utilization of residual dipolar couplings for structure determination of biological molecules; -summary of the sophisticated theoretical treatments, computer simulations, and phenomenological models for anisotropic intermolecular interactions that are widely used in the analysis of experimental results; -overview of the dynamical aspects and relaxation processes relevant for orientationally ordered molecules.

NMR Studies of Liquid Crystals and Molecules Dissolved in Liquid Crystal Solvents

NMR Studies of Liquid Crystals and Molecules Dissolved in Liquid Crystal Solvents PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 324

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Book Description
This thesis describes several studies in which nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure, orientation and dynamics of liquid crystal mesogens and molecules dissolved in liquid crystalline phases. In addition, a modern high field nmr spectrometer is described which has been used to perform such nmr studies. Chapter 1 introduces the quantum mechanical formalisms used throughout this thesis and briefly reviews the fundamentals of nuclear spin physics and pulsed nmr spectroscopy. First the density operator is described and a specific form for the canonical ensemble is derived. Then Clebsch-Gordon coefficients, Wigner rotation matrices, and irreducible tensor operators are reviewed. An expression for the equilibrium (Curie) magnetization is obtained and the linear response of a spin system to a strong pulsed r.f. irradiation is described. Finally, the spin interaction Hamiltonians relevant to this work are reviewed together with their truncated forms. Chapter 2 is a deuterium magnetic resonance study of two 'nom' liquid crystals which possess several low temperature mesomorphic phases. Specifically, deuterium quadrupolar echo spectroscopy is used to determine the orientation of the liquid crystal molecules in smectic phases, the changes in molecular orientation and motion that occur at smectic-smectic phase transitions, and the order of the phase transitions. For both compounds, the phase sequence is determined to be isotropic, nematic, smectic A, smectic C, smectic B{sub A}, smectic B{sub C}, and crystalline. The structure of the smectic A phase is found to be consistent with the well-known model of a two dimensional liquid in which molecules are rapidly rotating about their long axes and oriented at right angles to the plane of the layers. Molecules in the smectic C phase are found to have their long axes tilted with respect to the layer normal, and the tilt angle is temperature dependent, increasing from zero at the smectic A - smectic C transition and reaching a maximum at 9{sup o} at the smectic C - smectic B{sub A} transition. This finding contradicts the results of X-ray diffraction studies which indicate that the tilt angle is 18{sup o} and temperature independent. The smectic B{sub A} - smectic B{sub C} phase transition is observed for the first time, and is found to be first order, a result that contradicts the prediction of a mean theory by McMillian. Chapter 3 is a multiple quantum nmr study of n-hexane oriented in a nematic liquid crystal solvent. The basic three pulse multiple quantum experiment is discussed which enables the observation of transitions for which.

Solid-State NMR III Organic Matter

Solid-State NMR III Organic Matter PDF Author: Bernhard Blümich
Publisher: Springer Science & Business Media
ISBN: 3642612237
Category : Science
Languages : en
Pages : 218

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Book Description
Solid-State NMR is a branch of Nuclear Magnetic Resonance which is presently experiencing a phase of strongly increasing popularity. The most striking evidence is the large number of contributions from Solid-State Resonance atNMR meetings, approaching that ofliquid state resonance. Important progress can be observed in three areas: Methodological developments, applications to inorganic matter, and applications to organic matter. These developments are intented to be captured in three volumes in this series, each of them being devoted to more or less one of these areas. The present volume on Solid-State NMR III is devoted mainly to organic matter. The recent developments of deuteron NMR and their applications are reviewed in the first chapter. Crosspolarization, MAS, and dynamic angle spinning are being explored for enhancement of information and sensitivity. In addition to the analysis of classical relaxation times and modern 2D spectra, detailed dynamic information becomes accessible from investigations of the relaxation time anisotropies. The second chapter examines cross-polarization in static and rotating solids under conditions of spin diffusion and thermal motion. The underlying dipole-dipole interaction is further exploited by the techniques described in the third chapter for studies of polymer-polymer miscibility. Short range techniques are discriminated from long-range techniques based on spin diffusion. The use ofthese techniques is illustrated by a case study ofPMMAJPVF blends. The last chapter addresses novel z methods and applications of two-dimensional exchange NMR for investigations of relative molecular orientations, polymer morphology, molecular dynamics, and macroscopic molecular order.

Thermotropic Liquid Crystals

Thermotropic Liquid Crystals PDF Author: Ayyalusamy Ramamoorthy
Publisher: Springer Science & Business Media
ISBN: 1402053541
Category : Science
Languages : en
Pages : 331

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Book Description
This book covers developments in the field of thermotropic liquid crystals and their functional importance. It also presents advances related to different sub-areas pertinent to this interdisciplinary area of research. This text brings together research from synthetic scientists and spectroscopists and attempts to bridge the gaps between these areas. New physical techniques that are powerful in characterizing these materials are discussed.