Comb-Shaped Polymers and Liquid Crystals

ISBN-13: 9781461290827 / Angielski / Miękka / 2011 / 428 str.

Nikolai Al'fredovich Plate; V. P. Shibaev

Opis

to the American Edition We are pleased that our modest work, published some time ago in Russian in Moscow* and which attracted the attention of polymer specialists, t will now be available to the EngJish speaking audience of scientists - chemists, physicists, and technologists engaged in creating new types of polymer materi als for modern technology and working on the fundamental prob lems of the solid-state physics and structure of polymer- due to the initiative of Plenum Press. In polymer science, the 1980s were marked by the birth of a new field and a new scientific trend related to the dis covery and study of a previously unknown class of polymers thermotropic liquid-crystalline polymers - and the further development of the fundamental theoretical concepts of the liquid-crystalline (mesomorphic) state of macromolecular com pounds. This state is a phase state in thermodynamic equi librium characterized by the anisotropy of the structure and properties as a result of one-dimensional or two-dimensional ordering. Such systems have an ordered but simultaneously labile structure which can easily be altered by mechanical, electrical, or magnetic fields; the polymer system then acquires unique physical and optical properties. These prop erties, which are acquired in the liquid-crvstalline state, are then fixed in the solid at the operating temperatures. *N. A. Plate and V. P. Shibaev. Comb-Shaped Polymers and Li quid Crystals in RussianJ. Khimiya, Moscow (1980). tSee the review of this book by H. Mark in J. Polym. Sci. Polym. Lett. Ed., 20, 139 (L982).

Spis treści

1 Structure of Comb-Shaped Polymers.- 1.1. Early Studies.- 1.2. The Amorphous State.- 1.3. The Crystalline State of Isotactic Poly(l-alkyl ethylene)s, Poly(l-alkyl ethylene oxide)s, and Poly(alkyl aldehyde)s.- 1.4. The Rotational-Crystalline State.- 1.4.1. Hexagonal Packing.- 1.4.2. d Spacings. Single- and Two-Layer Packing of the Side Chains.- 1.4.3. Heats of Fusion, Length of Crystallizable Sequences of Units, and Convergence Temperature.- 1.5. Crystallization of Comb-Shaped Copolymers.- 1.6. Supermolecular Structure.- References.- 2 Molecular Mobility in Comb-Shaped Polymers.- 2.1. Effect of the Phase State on the Relaxation Properties.- 2.1.1. Polyethylene and Isotactic Poly(l-alkyl ethylene)s.- 2.1.2. Amorphous Comb-Shaped Polymers.- 2.1.3. Crystalline Comb-Shaped Polymers.- 2.1.4. Concluding Comments.- 2.2. Rheological Properties of Comb-Shaped Poly(alkyl acrylate)s and Poly(l-alkyl ethylene)s.- References.- 3 Comb-Shaped Macromolecules in Solutions and Intramolecular Interactions.- 3.1. Optical Anisotropy.- 3.2. Conformational State and Intramolecular Mobility.- 3.3. Unperturbed Dimensions of the Macromolecules.- 3.4. Gel Formation in Solutions of Comb-Shaped Polymers.- References.- 4 Thermotropic Liquid-Crystalline Polymers.- 4.1. General Information on the Formation and Structure of Low-Molecular-Weight Liquid Crystals.- 4.2. The Liquid-Crystalline State in Linear Polymers.- 4.3. Synthesis of Liquid-Crystalline Polymers with Mesogenic Side Groups and Some Features of the Formation of Mesophases.- 4.4. Comb-Shaped Liquid-Crystalline Polymers.- 4.5. Features of the Properties of Thermotropic Liquid-Crystalline Polymers Correlated with Their Macromolecular Nature.- 4.6. Theory of the Liquid-Crystalline Ordering of Melts of Linear and Branched Macromolecules with Mesogenic Groups in the Main and Side Chains.- 4.7. Mechanisms of the Formation and Properties of the Smectic, Nematic, and Cholesteric Mesophases of Liquid-Crystalline Polymers with Mesogenic Side Groups.- 4.7.1. Smectic Mesophases.- 4.7.1.1. Chemical Structure and Thermal Properties.- 4.7.1.2. Structure of Smectic Mesophases.- 4.7.1.2.a. SA Mesophases.- 4.7.1.2.b. SB, SE, and SF Mesophases and Other Types of Structures with Translationally Ordered Groups in Layers.- 4.7.1.2.c. SC Mesophases.- 4.7.1.3. Some General Comments on the Structure of Smectic Polymers.- 4.7.2. Nematic Mesophase.- 4.7.3. Comparison of Some Properties of Smectic and Nematic Liquid-Crystalline Polymers.- 4.7.3.1. Homopolymers.- 4.7.3.1.a. The Order Parameter.- 4.7.3.1.b. Rheological Properties.- 4.7.3.1.c. Molecular Mobility in the Solid State.- 4.7.3.2. Copolymers.- 4.7.3.2.a. Copolymers of Mesogenic and Nonmesogenic Monomers.- 4.7.3.2.b. Copolymers of Two Mesogenic Monomers.- 4.7.4. The Cholesteric Mesophase.- 4.7.4.1. Optical Properties.- 4.7.4.2. The Structure of Cholesteric Polymers.- 4.8. Behavior of Liquid-Crystalline Polymers in Electrical and Magnetic Fields.- 4.8.1. Orientational Effects.- 4.8.1.1. The Concept of Electro- and Magnetooptical Effects in Low- Molecular -Weight Liquid Crystals..- 4.8.1.2. Comb-Shaped Liquid-Crystalline Polymers.- 4.8.1.2.a. The Fredericks Transition (S Effect).- 4.8.1.2.b. Orientation in a Magnetic Field.- 4.8.1.2.c. The "Guest—Host" Effect.- 4.8.1.2.d. Optical Recording of Information (Thermal Addressing).- 4.8.1.2.e. The Structural Transition Induced by an Electric Field.- 4.8.2. Electrohydrodynamic Effects.- 4.9. Behavior of Liquid-Crystalline Polymers with Mesogenic Side Groups in Dilute Solutions.- References.