Liquid crystals : new perspectives / / coordinated by Pawel Pieranski, Maria Helena Godinho

• Pubblicazione: London, England : , : Wiley-ISTE, , [2021]; ©2021
• Descrizione fisica: 1 online resource (373 pages)
• Disciplina: 530.429
• Soggetto topico: Liquid crystals
• Persona (resp. second.): PieranskiPawel; GodinhoMaria Helena
• Nota di contenuto: Cover -- Half-Title Page -- Title Page -- Copyright Page -- Contents -- Preface -- 1. Singular Optics of Liquid Crystal Defects -- 1.1. Prelude from carrots -- 1.2. Liquid crystals, optics and defects: a long-standing trilogy -- 1.3. Polarization optics of liquid crystals: basic ingredients -- 1.3.1. The few liquid crystal phases at play in this chapter -- 1.3.2. Liquid crystals anisotropy and its main optical consequence -- 1.3.3. Polarization state representation in the paraxial regime -- 1.3.4. Polarization state evolution through uniform director fields -- 1.3.5. Effective birefringence -- 1.4. Liquid crystal reorientation under external fields -- 1.5. Customary optics from liquid crystal defects -- 1.5.1. Localized defects structures in frustrated cholesteric films -- 1.5.2. Elongated defects structures in frustrated cholesteric films -- 1.5.3. Regular optics from other topological structures -- 1.5.4. Assembling photonic building blocks with liquid crystal defects -- 1.6. From regular to singular optics -- 1.6.1. What is singular optics? -- 1.6.2. A nod to liquid crystal defects -- 1.6.3. Singular paraxial light beams -- 1.6.4. Generic singular beam shaping strategies -- 1.7. Advent of self-engineered singular optical elements enabled by liquid crystals defects -- 1.7.1. Optical vortices from a cholesteric slab: dynamic phase option -- 1.7.2. Optical vortices from a nematic droplet: geometric phase option -- 1.8. Singular optical functions based on defects: a decade of advances -- 1.8.1. Custom-made singular dynamic phase diffractive -- 1.8.2. Spontaneous singular geometric phase optics -- 1.8.3. Directed self-engineered geometric phase optics -- 1.8.4. From single to arrays of optical vortices -- 1.9. Emerging optical functionalities enabled by liquid crystal defects -- 1.9.1. Spectrally and spatially adaptive optical vortex coronagraphy. ; 1.9.2. Multispectral management of optical orbital angular momentum -- 1.10. Conclusion -- 1.11. References -- 2. Control of Micro-Particles with Liquid Crystals -- 2.1. Introduction -- 2.2. Control of micro-particles by liquid crystal-enabled electrokinetics -- 2.2.1. Liquid-crystal enabled electrophoresis -- 2.2.2. Liquid crystal-enabled electro-osmosis -- 2.3. Controlled dynamics of microswimmers in nematic liquid crystals -- 2.4. Conclusion -- 2.5. Acknowledgments -- 2.6. References -- 3. Thermomechanical Effects in Liquid Crystals -- 3.1. Introduction -- 3.2. The Ericksen-Leslie equations -- 3.2.1. Conservation equations -- 3.2.2. Molecular field -- 3.2.3. Constitutive equations -- 3.3. Molecular dynamics simulations of the thermomechanical effect -- 3.3.1. Molecular models -- 3.3.2. Constrained ensembles -- 3.3.3. Computation of the transport coefficients -- 3.3.4. Analysis of the results -- 3.4. Experimental evidence of the thermomechanical effect -- 3.4.1. The static Éber and Jánossy experiment -- 3.4.2. Another static experiment proposed in the literature -- 3.4.3. Continuous rotation of translationally invariant configurations -- 3.4.4. Drift of cholesteric fingers under homeotropic anchoring -- 3.5. The thermohydrodynamical effect -- 3.5.1. A proposal for measuring the TH Leslie coefficient μ: theoretical prediction -- 3.5.2. About the measurement of the TH Akopyan and Zel'dovich coefficients -- 3.6. Conclusions and perspectives -- 3.7. References -- 4. Physics of the Dowser Texture -- 4.1. Introduction -- 4.1.1. Disclinations and monopoles -- 4.1.2. Road to the dowser texture -- 4.1.3. The dowser texture -- 4.2. Generation of the dowser texture -- 4.2.1. Setups called "Dowsons Colliders" -- 4.2.2. "Classical" generation of the dowser texture -- 4.2.3. Accelerated generation of the dowser texture using the DDC2 setup. ; 4.3. Flow-assisted homeotropic ⇒ dowser transition -- 4.3.1. Experiment using the DDC2 setup -- 4.3.2. Flow-assisted bowser-dowser transformation in capillaries -- 4.3.3. Flow-assisted homeotropic-dowser transition in the CDC2 setup -- 4.3.4. Theory of the flow-assisted homeotropic-dowser transition -- 4.3.5. Summary and discussion of experimental results -- 4.4. Rheotropism -- 4.4.1. The first evidence of the rheotropism -- 4.4.2. Synchronous winding of the dowser field -- 4.4.3. Asynchronous winding of the dowser field -- 4.4.4. Hybrid winding of the dowser field with CDC2 -- 4.4.5. Rheotropic behavior of π- and 2π-walls -- 4.4.6. Action of an alternating Poiseuille flow on wound up dowser fields -- 4.5. Cuneitropism, solitary 2π-walls -- 4.5.1. Generation of π-walls by a magnetic field -- 4.5.2. Generation and relaxation of circular 2π-walls -- 4.5.3. Cuneitropic origin of the circular 2π-wall -- 4.6. Electrotropism -- 4.6.1. Definition of the electrotropism -- 4.6.2. Flexo-electric polarization -- 4.6.3. Setup -- 4.6.4. The first evidence of the flexo-electric polarization -- 4.6.5. Measurements of the flexo-electric polarization -- 4.7. Electro-osmosis -- 4.7.1. One-gap system of electrodes -- 4.7.2. Two-gap system of electrodes -- 4.7.3. Convection of the dowser field -- 4.8. Dowser texture as a natural universe of nematic monopoles -- 4.8.1. Structures and topological charges of nematic monopoles -- 4.8.2. Pair of dowsons d+ and d- seen as a pair of monopoles -- 4.8.3. Generation of monopole-antimonopole pairs by breaking 2π-walls -- 4.9. Motions of dowsons in a wound up dowser field -- 4.9.1. Single dowson in a wound up dowser field -- 4.9.2. The Lorentz-like force -- 4.9.3. Velocity of dowsons in wound up dowser fields -- 4.9.4. The race of dowsons -- 4.9.5. Trajectories of dowsons observed in natural light. ; 4.9.6. Trajectories of dowsons observed in polarized light -- 4.10. Collisions of dowsons -- 4.10.1. Pair of dowsons (d+,d-) inserted in a wound up dowser field -- 4.10.2. Cross-section for annihilation of dowsons' pairs -- 4.10.3. Rheotropic control of the collisions outcome -- 4.11. Motions of dowsons in homogeneous fields -- 4.12. Stabilization of dowsons systems by inhomogeneous fields with defects -- 4.12.1. Gedanken experiment -- 4.12.2. Triplet of dowsons stabilized in MBBA by a quadrupolar electric field -- 4.12.3. Septet of dowsons in MBBA stabilized by a quadrupolar electric field -- 4.12.4. Dowsons d+ stabilized by corner singularities of the electric field -- 4.13. Dowser field submitted to boundary conditions with more complex geometries and topologies -- 4.13.1. Ground state of the dowser field in an annular droplet -- 4.13.2. Wound up metastable states of the dowser field in the annular droplet -- 4.13.3. Dowser field in a square network of channels, four-arm junctions -- 4.13.4. Triangular network, six-arm junctions -- 4.13.5. Three-arm junctions -- 4.13.6. General discussion of n-arm junctions -- 4.14. Flow-induced bowson-dowson transformation -- 4.15. Instability of the dowson's d- position in the stagnation point -- 4.16. Appendix 1: equation of motion of the dowser field -- 4.16.1. Elastic torque -- 4.16.2. Viscous torques -- 4.16.3. Magnetic torque -- 4.16.4. Electric torque -- 4.17. References -- 5. Spontaneous Emergence of Chirality -- 5.1. Introduction -- 5.2. Chirality: a historical tour -- 5.2.1. Chirality and optics -- 5.2.2. Chiral symmetry breaking and its misuse -- 5.2.3. Spontaneous emergence of chirality or chiral structures in liquid crystals -- 5.2.4. Spontaneous emergence of chirality due to confinement -- 5.2.5. Spontaneous emergence of chirality due to cylindrical confinement. ; 5.2.6. Some misconceptions about optical rotation -- 5.3. Concluding remarks -- 5.4. Acknowledgments -- 5.5. References -- List of Authors -- Index -- EULA.
• Sommario/riassunto: This book on liquid crystals reports on the new perspectives that have been brought about by the recent expansion of frontiers and overhaul of common beliefs. First, it explores the interaction of light with mesophases, when the light or matter is endowed with topological defects. It goes on to show how electrophoresis, electro-osmosis and the swimming of flagellated bacteria are affected by the anisotropic properties of liquid crystals. It also reports on the recent progress in the understanding of thermomechanical and thermohydrodynamical effects in cholesterics and deformed nematics and refutes the common belief that these effects could explain Lehmann's observations of the rotation of cholesteric droplets subjected to a temperature gradient. It then studies the physics of the dowser texture, which has remarkable properties. This is of particular interest in regards to nematic monopoles, which can easily be generated, set into motion and collided within it. Finally, this book deals with the spontaneous emergence of chirality in nematics made of achiral molecules, and provides a brief historical context of chirality.
• Titolo autorizzato: LIQUID crystals
• ISBN: 1-119-85078-9; 1-119-85080-0; 1-119-85079-7
• Formato: Materiale a stampa
• Livello bibliografico: Monografia
• Lingua di pubblicazione: Inglese
• Record Nr.: 9910830145703321
• Lo trovi qui: Univ. Federico II