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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.
Sommario
1. A Comparative Survey of the Physical Techniques Used in Studies of Molecular Dynamics.- 2. On the Description of Ordering in Liquid Crystals.- 3. Diffusion Models for Molecular Motion in Uniaxial Mesophases.- 4. ESR and Liquid Crystals: Statistical Mechanics and Generalised Smoluchowski Equations.- 5. Techniques and Applications of Langevin Dynamics Simulations.- 6. An Introduction to the Molecular Dynamics Method and to Orientational Dynamics in Liquid Crystals.- 7. Nuclear Spin Relaxation Formalism for Liquid Crystals.- 8. Nuclear Spin Relaxation and Molecular Motion in Liquid Crystals.- 9. The Effects of Director Fluctuations on Nuclear Spin Relaxation.- 10. Nuclear Spin Relaxation Mechanisms in Liquid Crystals Studied By Field Cycling NMR.- 11. Probe Studies of Liquid Crystals.- 12. ESR and Molecular Motions in Liquid Crystals: Motional Narrowing.- 13. Thermodynamics of Liquid Crystals and the Relation to Molecular Dynamics: ESR Studies.- 14. ESR Studies of Molecular Dynamics at Phase Transitions in Liquid Crystals.- 15. ESR and Slow Motions in Liquid Crystals.- 16. Raman and IR Fluctuation Spectroscopy of Liquid Crystals.- 17. Dielectric Relaxation Behaviour of Liquid Crystals.- 18. Neutron Scattering From Liquid Crystals.- 19. Molecular Order and Motion in Liquid Crystal Polymers Studied By Pulsed Dynamic NMR.- 20. Aggregates of Amphiphiles in Lyotropic Liquid Crystals.- 21. Orientation and Frequency Dependent NMR Relaxation Studies of Bilayer Membranes: Characterisation of the Lipid Motions.- 22. Molecular Dynamics in Liquid-Crystalline Systems Studied By Fluorescence Depolarisation Techniques.- 23. Spectroscopic Studies on Structure and Dynamics of Lyotropic Liquid Crystals: Cubic and Reversed Hexagonal Phases and Lipid Vesicles.
