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Lyotropic Chromonic Liquid Crystals: from Viscoelastic Properties to Living

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LYOTROPIC CHROMONIC LIQUID CRYSTALS: FROM VISCOELASTIC PROPERTIES TO LIVING LIQUID CRYSTALS A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Shuang Zhou May, 2016 © Copyright All rights reserved Except for previously published materials Dissertation written by Shuang Zhou B. S., Xi’an Jiaotong University, China, 2003 Ph.D., Kent State University, USA, 2016 Approved by Dr. Oleg D. Lavrentovich , Chair, Doctoral Dissertation Committee Dr. Peter Palffy-Muhoray , Members, Doctoral Dissertation Committee Dr. Qi-Huo Wei , Dr. Samuel Sprunt , Dr. Roger Gregory , Accepted by Dr. Hiroshi Yokoyama , Chair, Chemical Physics Interdisciplinary Program Dr. James L. Blank , Dean, College of Arts and Sciences ii TABLE OF CONTENTS LIST OF FIGURES ...................................................................................................... VII LIST OF TABLES .........................................................................................................XV DEDICATION.............................................................................................................. XVI ACKNOWLEDGEMENTS ...................................................................................... XVII CHAPTER 1 INTRODUCTION ..................................................................................... 1 1.1 Lyotropic Chromonic Liquid Crystals ...................................................................... 1 1.2 Active Colloids and Collective Behavior .................................................................. 6 1.3 Scope and Objectives of the Dissertation ................................................................ 13 CHAPTER 2 ELASTICITY OF LYOTROPIC CHROMONIC LIQUID CRYSTALS PROBED BY DIRECTOR REORIENTATION IN MAGNETIC FIELD ........................................................................................... 18 2.1 Introduction ............................................................................................................. 18 2.2 Samples and Experimental Set-up ........................................................................... 20 2.3 Results ..................................................................................................................... 22 2.3.1 Homeotropic cells, bend constant K3 ........................................................... 22 2.3.2 Planar cells, splay constant K1 ...................................................................... 24 2.3.3 Planar cells, twist constant K2 ...................................................................... 25 2.4 Discussion and Conclusion ..................................................................................... 26 2.5 Supplemental Information ....................................................................................... 32 2.5.1 Estimation of average aggregation length ..................................................... 32 2.5.2 Measurement of ..................................................................................... 34 iii 2.5.3 Volume fraction measurements ..................................................................... 35 2.5.4 Optical response of bend distortion ............................................................... 38 2.5.5 Optical simulation to determine splay constant K1 ...................................... 39 2.5.6 Planar cells, twist constant K2 ...................................................................... 42 CHAPTER 3 IONIC-CONTENT DEPENDENCE OF VISCOELASTICITY OF THE LYOTROPIC CHROMONIC LIQUID CRYSTAL SUNSET YELLOW............................................................................................................. 46 3.1 Introduction ............................................................................................................. 46 3.2 Material and Methods .............................................................................................. 47 3.2.1 LCLC SSY with ionic additives .................................................................... 49 3.2.2 Viscoelastic constants measurement ............................................................. 50 3.3 Results ..................................................................................................................... 50 3.3.1 Splay constant K1 ......................................................................................... 50 3.3.2 Bend constant K3 .......................................................................................... 54 3.3.3 Twist constant K2 ......................................................................................... 56 3.3.4 Rotation viscosity 1 .................................................................................... 58 3.4 Conclusion ............................................................................................................... 60 3.5 Supplemental Information ....................................................................................... 61 3.5.1 Estimation of Ee ........................................................................................... 61 3.5.2 Measurement of volume fraction .............................................................. 62 3.5.3 Measurement of rotation viscosity 1 ........................................................... 63 iv CHAPTER 4 : ELASTICITY, VISCOSITY, AND ORIENTATIONAL FLUCTUATIONS OF A LYOTROPIC CHROMONIC NEMATIC LIQUID CRYSTAL DISODIUM CROMOGLYCATE ................................................. 67 4.1 Introduction ............................................................................................................. 67 4.2 Experimental Details ............................................................................................... 69 4.2.1 Materials ........................................................................................................ 69 4.2.2 Experimental set-up....................................................................................... 71 4.3 Results ..................................................................................................................... 75 4.3.1 Elastic constants ............................................................................................ 75 4.3.2 Viscosities ..................................................................................................... 78 4.3.3 An additional mode in bend geometry .......................................................... 81 4.4 Discussion ............................................................................................................... 82 4.4.1 Elastic constants ............................................................................................ 83 4.4.2 Viscosities ..................................................................................................... 93 4.4.3 Origin of the additional fluctuation mode in the bend geometry .................. 95 4.5 Conclusions ........................................................................................................... 101 CHAPTER 5 : LIVING LIQUID CRYSTALS .......................................................... 103 5.1 Introduction ........................................................................................................... 103 5.2 Materials and Methods .......................................................................................... 104 5.2.1 Bacteria........................................................................................................ 104 5.2.2 LLC preparation .......................................................................................... 105 5.2.3 Videomicroscopy ........................................................................................ 105 v 5.2.4 PolScope microscopy .................................................................................. 106 5.3 Results ................................................................................................................... 106 5.3.1 Single bacteria motion ................................................................................. 109 5.3.2 Collective behavior ..................................................................................... 112 5.4 Discussion and conclusion .................................................................................... 117 5.5 Supplemental information ..................................................................................... 120 5.5.1 Optics of director patterns in the wake of a moving bacterium .................. 120 5.5.2 Optics of director patterns distorted by flows produced by individual bacterium ................................................................................................................. 122 CHAPTER 6 SUMMARY ............................................................................................ 127 REFERENCES .............................................................................................................. 132 vi LIST OF FIGURES Figure 1.1: Molecular structures of some lyotropic chromonic liquid crystal materials. ... 2 Figure 1.2: Molecular structure and schematic of a SSY-water LCLC. (a) Molecular structure and schematic of disassociation of sodium ions from a single molecule in water. (b) Schematic of SSY assembly in water (represented by the blue background) to form nematic LCLC; aromatic centers stack on top of each other while the sodium ions are disassociated, leaving the aggregates
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