Theoretical Predictions for Side-chain Liquid-crystal Polymers and Comparison to Experiment

Theoretical Predictions for Side-chain Liquid-crystal Polymers and Comparison to Experiment
Author:
Publisher:
Total Pages:
Release: 1988
Genre:
ISBN:

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This paper presents results from a new unique microscopic molecular theory for side-chain liquid-crystalline polymers (LCPs) in the nematic (N) and multiple smectic-A (SA) LC phases and the isotropic (I) liquid phase. There are no ad hoc or arbitrarily adjustable parameters in this theory. The agreement between the theoretical and experimental values for various properties (including transition temperatures and quadratic characteristic radii) is very good (relative deviations between 0% and less than 6.2%). The theoretical results also show--for the first time--that the N and I phases for these LCPs involve the packing of plate-like sections of backbones and side chains and that the local bilayer SA phase involves packing of side-chains within a plate-like section. This type of packing is predicted to be typical for side-chain LCPs. This theory can predict--for the first time--whether the side chains of a molecule pack on the same or alternating opposite sides of the backbone and whether side chains on different molecules interdigitate (overlap) with each other. 13 refs., 1 fig., 4 tabs.

New Theories for Smectic and Nematic Liquid-crystal Polymers

New Theories for Smectic and Nematic Liquid-crystal Polymers
Author:
Publisher:
Total Pages:
Release: 1987
Genre:
ISBN:

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A summary of predictions and explanations from statistical-physics theories for both backbone and side-chain liquid crystalline polymers (LCPs) and for mixtures with backbone LCPs are presented. Trends in the thermodynamic and molecular ordering properties have been calculated as a function of pressure, density, temperature, and molecule chemical structures (including degree of polymerization and the following properties of the chemical structures of the repeat units: lengths and shapes, intra-chain rotation energies, dipole moments, site-site polarizabilities and Lennard-Jones potentials, etc.) in nematic and multiple smectic-A LC phases and in the isotropic liquid phase. The theoretical results are found to be in good agreement with existing experimental data. These theories can also be applied to combined LCPs. Since these theories have no ad hoc or arbitrarily adjustable parameters, these theories can be used to design new LCPs and new solvents as well as to predict and explain properties. 27 refs., 4 tabs.

Side Chain Liquid Crystal Polymers

Side Chain Liquid Crystal Polymers
Author: C.B. McArdle
Publisher: Springer Science & Business Media
Total Pages: 474
Release: 1990-04-30
Genre: Technology & Engineering
ISBN: 9780216925038

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Biaxial Nematic Liquid Crystals

Biaxial Nematic Liquid Crystals
Author: Geoffrey R. Luckhurst
Publisher: John Wiley & Sons
Total Pages: 408
Release: 2015-02-23
Genre: Science
ISBN: 1118696336

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In the nematic liquid crystal phase, rod-shaped molecules move randomly but remain essentially parallel to one another. Biaxial nematics, which were first predicted in 1970 by Marvin Freiser, have their molecules differentially oriented along two axes. They have the potential to create displays with fast switching times and may have applications in thin-film displays and other liquid crystal technologies. This book is the first to be concerned solely with biaxial nematic liquid crystals, both lyotropic and thermotropic, formed by low molar mass as well as polymeric systems. It opens with a general introduction to the biaxial nematic phase and covers: • Order parameters and distribution functions • Molecular field theory • Theories for hard biaxial particles • Computer simulation of biaxial nematics • Alignment of the phase • Display applications • Characterisation and identification • Lyotropic, thermotropic and colloidal systems together with material design With a consistent, coherent and pedagogical approach, this book brings together theory, simulations and experimental studies; it includes contributions from some of the leading figures in the field. It is relevant to students and researchers as well as to industry professionals working in soft matter, liquid crystals, liquid crystal devices and their applications throughout materials science, chemistry, physics, mathematics and display engineering.

Publications of Los Alamos Research

Publications of Los Alamos Research
Author: Los Alamos National Laboratory
Publisher:
Total Pages: 276
Release: 1989
Genre: Research
ISBN:

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Energy Research Abstracts

Energy Research Abstracts
Author:
Publisher:
Total Pages: 620
Release: 1990
Genre: Power resources
ISBN:

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Macromolecular Microsymposia—XII and XIII

Macromolecular Microsymposia—XII and XIII
Author: B. Sedláček
Publisher: Elsevier
Total Pages: 285
Release: 2013-10-22
Genre: Science
ISBN: 148328476X

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Macromolecular Microsymposia–XII and XIII provides information pertinent to the fundamental aspects of polymers and polymer solutions. This book discusses the structures in polymer solutions and the transformations of functional groups in polymers. Organized into two parts encompassing 15 chapters, this book begins with an overview of the method for the determination of the structure of block copolymers in concentrated solution and in the dry state. This text then examines the liquid crystalline mesophases of the cholesteric type where one requirement is the existence of chiral single molecules. Other chapters consider phospholipids and glycolipids, which are significant component of the structure of many cell membranes. This book discusses as well the organized structures of some synthetic macromolecules in gels and solutions. The final chapter deals with the technique for studying the effect of the excluded volume on the probability of cyclic chain conformations. This book is a valuable resource for chemists.

Liquid Crystal Polymers

Liquid Crystal Polymers
Author: D. Coates
Publisher: iSmithers Rapra Publishing
Total Pages: 190
Release: 2000
Genre: Technology & Engineering
ISBN: 9781859572146

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Liquid crystal polymers (LCPs) have a wide range of uses, from strong engineering plastics to delicate gels for use in liquid crystal (LC) displays. For this reason, it is essential reading for materials scientists, engineers or technologists in industry, as well as research laboratories or academia. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.

Rheology and Processing of Liquid Crystal Polymers

Rheology and Processing of Liquid Crystal Polymers
Author: Domenico Acierno
Publisher: Springer Science & Business Media
Total Pages: 331
Release: 2013-11-27
Genre: Technology & Engineering
ISBN: 940091511X

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Liquid crystal polymers (LCPs) have many strange properties that may be utilized to advantage in the processing of products made from them and their blends with isotropic polymers. This volume (volume 2 in the series Polymer Liquid Crystals) deals with their strange flow behaviour and the models put forward to explain the phenomena that occur in such polymers and their blends. It has been known for some time that small ad ditions of a thermotropic LCP to isotropic polymers not only gives an improvement in the strength and stiffness of the blend but improves the processability of the blend over that of the isotropic polymer. In the case of lyotropic LCPs, it is possible to create a molecular composite in which the reinforcement of an isotropic polymer is achieved at a molecular level by the addition of the LCP in a common solvent. If the phenomena can be fully understood both the reinforcement and an increase in the proces sability of isotropic polymers could be optimized. This book is intended to illustrate the current theories associated with the flow of LCPs and their blends in the hope that such an optimization will be achieved by future research. Chapter 1 introduces the subject of LCPs and describes the ter minology used; Chapter 2 then discusses the more complex phenomena associated with these materials. In Chapter 3, the way in which these phe nomena may be modelled using hamiltonians is fully covered.