139,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
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
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 584
Veröffentlichungsjahr: 2021
Ähnliche
Table of Contents
Cover
Title Page
Copyright
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
1.4. Liquid crystal reorientation under external fields
1.5. Customary optics from liquid crystal defects
1.6. From regular to singular optics
1.7. Advent of self-engineered singular optical elements enabled by liquid crystals defects
1.8. Singular optical functions based on defects: a decade of advances
1.9. Emerging optical functionalities enabled by liquid crystal defects
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
2.3. 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
3.3. Molecular dynamics simulations of the thermomechanical effect
3.4. Experimental evidence of the thermomechanical effect
3.5. The thermohydrodynamical effect
3.6. Conclusions and perspectives
3.7. References
4 Physics of the Dowser Texture
4.1. Introduction
4.2. Generation of the dowser texture
4.3. Flow-assisted homeotropic ⇒ dowser transition
4.4. Rheotropism
4.5. Cuneitropism, solitary 2π-walls
4.6. Electrotropism
4.7. Electro-osmosis
4.8. Dowser texture as a natural universe of nematic monopoles
4.9. Motions of dowsons in a wound up dowser field
4.10. Collisions of dowsons
4.11. Motions of dowsons in homogeneous fields
4.12. Stabilization of dowsons systems by inhomogeneous fields with defects
4.13. Dowser field submitted to boundary conditions with more complex geometries and topologies
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
4.17. References
5 Spontaneous Emergence of Chirality
5.1. Introduction
5.2. Chirality: a historical tour
5.3. Concluding remarks
5.4. Acknowledgments
5.5. References
List of Authors
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1.
Connection between various polarization quantities
Chapter 3
Table 3.1. Average values of the LTP (in unit of 10−8 N m−1 K−1wt%−1) of the HTP...
Table 3.2. Values at the transition temperature of the main physical constants o...
Guide
Cover
Table of Contents
Title Page
Copyright
Preface
Begin Reading
List of Authors
Index
End User License Agreement
Pages
v
iii
iv
xi
xii
xiii
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
349
350
351
352
353
354
355
SCIENCES
Physics of Soft Matter, Field Director – Françoise Brochard-Wyart
Lyotropic and Thermotropic Liquid Crystals, Subject Heads – Pawel Pieranski and Maria Helena Godinho
Liquid Crystals
New Perspectives
Coordinated by
Pawel Pieranski
Maria Helena Godinho
First published 2021 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd27-37 St George’s RoadLondon SW19 4EUUK
www.iste.co.uk
John Wiley & Sons, Inc.111 River StreetHoboken, NJ 07030USA
www.wiley.com
© ISTE Ltd 2021
The rights of Pawel Pieranski and Maria Helena Godinho to be identified as the author of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.
Library of Congress Control Number: 2021934282
British Library Cataloguing-in-Publication DataA CIP record for this book is available from the British LibraryISBN 978-1-78945-040-8
ERC code:
PE3 Condensed Matter Physics
PE3_13 Structure and dynamics of disordered systems: soft matter (gels, colloids, liquid crystals, etc.), liquids, glasses, defects, etc.
Preface
The story of liquid crystals is that of a transgression of frontiers and a breaking of common beliefs.
Indeed, liquid crystals were discovered by a biochemist, Friedrich Reinitzer, who shared his perplexity with a physicist, Otto Lehmann. Subsequently, crystallographers, mineralogists, experts in optics, magnetism, thermodynamics, chemists, etc., contributed to the recognition of liquid crystals as new states of matter, called mesophases by George Friedel, endowed with structures intermediate to those of isotropic liquids and crystals.
Mesophases are so fragile that they can be easily perturbed by moderate mechanical, electric, magnetic or thermal stresses that generate various defects, such as disclinations, dislocations, walls, monopoles or multipoles. Remarkably, these defects were also observed to appear spontaneously during phase transitions.
Inspired by experimental discoveries, theorists and mathematicians became fascinated by the symmetries of mesophases and recognized these beautiful and mysterious defects as topological singularities of vectorial, tensorial or complex fields. This led to the introduction of the concept of order parameters, resulting from symmetry breaking. In this frame, the generation of topological defects during certain phase transitions appeared as a natural, expected consequence. It was thus appreciated that the physics of liquid crystals and their defects had a permeable border with the Kibble–Zurek mechanism in cosmology.
The discovery of liquid crystals was made in substances extracted from carrots. Prior to that, Mettenheimer and Virchov observed birefringent lamellar mesophases in aqueous solutions of myelin, a substance extracted from nerve tissues. Mesophases also appear in solutions of cellulosic compounds or in suspensions of elongated particles, such as cellulose nanocrystals, tobacco mosaic viruses or bacteria. Therefore, from their origin, liquid crystals share a border with living matter.
In this book, the borders with cosmology and living matter, as well as other borders will be crossed several times. The title Liquid Crystals – New Perspectives announces that when borders are crossed, new perspectives are unlocked.
The first chapter, Singular Optics of Liquid Crystal Defects, explores a terra incognita: the light–matter interaction that occurs when light and/or matter are endowed with topological defects. It tells how the physics of topological defects in liquid crystals has progressively enriched liquid crystal optics as singular optics have developed. This is rooted in a few generic features: the self-organization capabilities of soft matter systems and their sensitivity to external stimuli. Remarkably, all of the assets of liquid crystals that make them ubiquitous in our daily life as liquid crystal displays, now open up several options to explore fundamental optical phenomena, based on the coupling between the polarization and spatial degrees of freedom. Also, this allows us to envision the development of future applications, for instance in optical imaging, beam shaping and the manipulation of matter by light.
The second chapter, Control of Micro-Particles with Liquid Crystals, transgresses two frontiers. First, that between liquid crystals and electro-kinetic phenomena. The authors show how electrophoresis and electro-osmosis, well known from studies with isotropic liquids, acquire new unexpected features when the anisotropy and nonlinear hydrodynamics of liquid crystals are switched on. The second transgression is that of the frontier with living matter. The quasi-random swimming motion of flagellated bacteria in isotropic liquids becomes ordered in lyotropic liquid crystals and even more fascinating in the presence of topological defects, disclinations.
The third chapter, Thermomechanical Effects in Liquid Crystals, crosses the border between liquid crystals and out-of-equilibrium thermodynamics. Anisotropy and nonlinear hydrodynamics of liquid crystals radically alter the phenomena driven by thermal gradients. For example, the threshold of the Rayleigh–Bénard instability in nematics is known to be lowered by a factor of 1000 with respect to isotropic liquids. The thermomechanical and thermohydrodynamical effects discussed in this chapter are even more original because they do not exist in isotropic fluids. Once again, they become fascinating in the presence of topological defects. This chapter breaks the common belief about a unique explanation, in terms of the Leslie theory, of the Lehmann effect, i.e. the rotation of cholesteric droplets driven by a thermal gradient.
The fourth chapter, Physics of the Dowser Texture, transgresses the common belief about the ephemeral character of a distorted nematic texture, bearing varying names in the past: splay-bend state, H state, inversion wall, quasi-planar or flow-aligned. Dubbed as the dowser texture because of its resemblance with the wooden tool of dowsers, this texture is in fact not unstable but only metastable and in certain conditions can be preserved indefinitely. As its complex order parameter eiϕ is degenerated with respect to the phase ϕ, the dowser texture is sensitive to vector fields and as a consequence it is endowed with unprecedented properties called cuneitropism, rheotropism and electrotropism. The dowser texture also appears as a natural universe of nematic monopoles and antimonopoles that can be set in motion and brought to collisions, resulting in the annihilation of monopole–antimonopole pairs, analogous to the annihilation of electron-positron pairs in hadron colliders.
The fifth chapter, Spontaneous Emergence of Chirality, deals with nematics, which are made up of achiral molecules. It begins with a very detailed historical tour leading to the birth of the concept of chirality. The tour starts with the discovery of double refraction in Iceland spar crystals by Erasmus Bartolinus in 1669, followed by the crucial contributions of Huygens, Malus, Arago, Brewster, Biot, Fresnel and Faraday, leading to the epoch marking the discovery of molecular chirality by Louis Pasteur. The work of Pasteur gave birth to a common belief that the optical activity of materials results from the existence of molecular chirality. The observations of chiral textures in lyotropic nematics discussed in this fifth chapter break this common belief and unlock new perspectives.
We would like to thank Mme Françoise Brochard-Wyart for the invitation to write this book. Its contours were fixed thanks to Tigran Galstian, who invited six of the authors to the 18th Conference on Optics of Liquid Crystals, in Quebec.
The printing in color of this book was sponsored by : 1) Marie Curie Grant N¡838199, 2) Department of Physics and Materials Science at The University of Memphis, Memphis, Tennessee (USA), 3) National Science Foundation (USA) grant DMR-1905053 entitled “Active colloids with tunable interactions in liquid crystals”, 4) Laboratoire de Physique at Ecole Normale Supérieure de Lyon, Lyon (France), 5) Laboratoire de Physique des Solides at Université Paris-Saclay, Orsay (France), 6) i3N/CENIMAT, NOVA School of Science and Technology, NOVA University of Lisbon (Portugal), 7) School of Materials Science and Engineering at Georgia Institute of Technology, Atlanta, Georgia (USA).
The writing of this book lasted for about one year. Once the work was finished, we were tempted to say, following the Eulogy of Leonhard Euler by Marquis de Condorcet, that:
...the pleasure to work is a sweeter reward than glory...
On behalf of all the authorsMarch 2021
