The aim of this book is to give a unified and critical account of the fundamental aspects of liquid crystals. Preference is given to discussing the assumptions made in developing theories and analyzing experimental data rather than to attempting to compile all the latest results. The book has four parts. Part I is quite descriptive in character and gives a general overview of the various liquid crystalline phases. Part II deals with the macroscopic continuum theory of liquid crystals and gives a systematic development of the theory from a tensorial point of view thus emphasizing the relevant symmetries. Part III concentrates on experiments that provide microscopic information on the orientational behaviour of the molecules. Finally Part IV discusses the theory of the various phases and their attendant phase transitions from both a Landau and a molecular-statistical point of view. Simplifying the various models as far as possible, it critically examines the merits of a molecular-statistical approach.

Inhalt

I Mesomorphic Behaviour.- 1. Introduction.- 1.1 Mesomorphic Behaviour.- 1.2 Mesogenic Compounds.- 1.3 Classification of the Mesophases.- 2. Nematic Liquid Crystals.- 2.1 Nematics Proper.- 2.2 Chiral Nematics.- 3. Smectic Liquid Crystals.- 3.1 Broken Symmetry and the Organization of Smectics.- 3.2 Smectics with Liquid Layers.- 3.2.1 Smectics A.- 3.2.2 Smectics C.- 3.3 Smectics with Bond-Orient at ional Order.- 3.4 Smectics with Ordered Layers.- 4. Other Liquid Crystalline Systems.- 4.1 Cubic Thermotropic Mesophases.- 4.2 Mesophases of Disc-Like Molecules.- 4.3 Liquid Crystalline Polymers.- 4.3.1 Liquid Crystalline Main-Chain Polymers.- 4.3.2 Liquid Crystalline Side-Chain Polymers.- 4.4 Lyotropic Liquid Crystals.- II Continuum Theory.- 5. Static Continuum Theory.- 5.1 Cartesian Tensors.- 5.2 Macroscopic Order Parameter.- 5.3 The Frank Free Energy.- 5.4 General Properties of the Director Field.- 5.5 Appendix.- 6. Effects of External Fields.- 6.1 Interaction Between Applied Fields and Director Fields.- 6.2 Frederiks Transitions.- 6.3 The Cholesteric-Nematic Transition.- 6.4 Elastic Constants and Molecular Structure.- 7. Applications of Continuum Theory.- 7.1 Disclinations.- 7.1.1 The Axial Disclination Line.- 7.1.2 The Perpendicular Disclination Line.- 7.2 Fluctuations in the Nematic Phase.- 7.3 Light Scattering by Nematics.- 7.4 Optical Properties of Chiral Nematics.- 7.4.1 Introduction.- 7.4.2 General Theory.- 7.5 Correlations in the Smectic A Phase.- 8. Fluid Dynamics of Nematics.- 8.1 Fluid Dynamics of Isotropic Liquids.- 8.2 Nematodynamics.- 8.3 Viscosity Measurements.- 8.4 Electrohydrodynamic Instabilities.- III Orientational Order and Anisotropic Properties.- 9. Orientational Order.- 9.1 Microscopic Order Parameters.- 9.2 Magnetic Anisotropy.- 9.3 Nuclear Magnetic Resonance.- 9.4 Polarized Raman Scattering.- 9.5 X-Ray Scattering.- 10. Anisotropic Physical Properties.- 10.1 The Refractive Index.- 10.2 The Dielectric Permittivity.- 10.3 Transport Properties.- 10.3.1 Mass Diffusion.- 10.3.2 Electrical Conduction.- 11. Dynamic Behaviour of the Molecules.- 11.1 Neutron Scattering.- 11.2 Nuclear Magnetic Resonance and Relaxation.- 11.3 Dielectric Relaxation.- IV Liquid Crystalline Phases and Phase Transitions.- 12. Landau Theory of Liquid Crystalline Phases.- 12.1 The Basic Ideas of Landau Theory.- 12.2 The Nematic-Isotropic Transition.- 12.3 Fluctuations in the Isotropic Phase.- 12.4 The Smectic-Nematic Transition.- 13. Molecular Statistical Theory of the Nematic Phase.- 13.1 Introduction to the Theory of Simple Liquids.- 13.2 The Equation of State of Nematics.- 13.3 The Onsager Approach.- 13.4 The Maier-Saupe Approach.- 13.5 Theory of the Chiral Nematic Phase.- 13.6 On the Relevance of Molecular Models.- 14. Molecular Statistical Theory of the Smectic Phases.- 14.1 Theory of the Smectic A-Nematic Transition.- 14.1.1 The Meyer-Lubensky Model.- 14.1.2 The Kobayashi-McMillan Model.- 14.2 Theory of the Smectic C Phase.- 14.3 Theory of the Chiral Smectic C Phase.- References.- Index of Compounds.