Fluids, Colloids and Soft Materials: An Introduction to Soft Matter Physics(Wiley Series on Surface and Interfacial Chemistry)

This book presents a compilation of self-contained chapters covering a wide range of topics within the broad field of soft condensed matter. Each chapter starts with basic definitions to bring the reader up-to-date on the topic at hand, describing how to use fluid flows to generate soft materials of high value either for applications or for basic research. Coverage includes topics related to colloidal suspensions and soft materials and how they differ in behavior, along with a roadmap for researchers on how to use soft materials to study relevant physics questions related to geometrical frustration.

Table of Contents:
Preface xv List of Contributors xvii SECTION I FLUID FLOWS 1 1 Drop Generation in Controlled Fluid Flows 3 Elena Castro Hernandez, Josefa Guerrero, Alberto Fernandez-Nieves, & Jose M. Gordillo 1.1 Introduction, 3 1.2 Coflow, 4 1.2.1 Problem and Dimensionless Numbers, 4 1.2.2 Dripping and Jetting, 5 1.2.3 Narrowing Jets, 6 1.2.4 Unified Scaling of the Drop Size in Both Narrowing and Widening Regimes, 7 1.2.5 Convective Versus Absolute Instabilities, 9 1.3 Flow Focusing, 12 1.4 Summary and Outlook, 15 References, 15 2 Electric Field Effects 19 Francisco J. Higuera 2.1 Introduction, 19 2.2 Mathematical Formulation and Estimates, 20 2.2.1 Conical Meniscus, 22 2.2.2 Cone-to-Jet Transition Region and Beyond, 23 2.2.3 Very Viscous Liquids, 24 2.3 Applications and Extensions, 24 2.3.1 Multiplexing, 24 2.3.2 Coaxial Jet Electrosprays, 25 2.3.3 Electrodispersion in Dielectric Liquid Baths, 26 2.4 Conclusions, 27 References, 27 3 Fluid Flows for Engineering Complex Materials 29 Ignacio G. Loscertales 3.1 Introduction, 29 3.2 Single Fluid Micro- or Nanoparticles, 30 3.2.1 Flows Through Micron-Sized Apertures, 31 3.2.2 Microflows Driven by Hydrodynamic Focusing, 33 3.2.3 Micro- and Nanoflows Driven by Electric Forces, 34 3.3 Steady-state Complex Capillary Flows for Particles with Complex Structure, 36 3.3.1 Hydrodynamic Focusing, 36 3.3.2 Electrified Coaxial Jet, 38 3.4 Summary, 39 Acknowledgments, 41 References, 41 SECTION II COLLOIDS IN EXTERNAL FIELDS 43 4 Fluctuations in Particle Sedimentation 45 P.N. Segrè 4.1 Introduction, 45 4.2 Mean Sedimentation Rate, 45 4.2.1 Brownian Sedimentation, 46 4.2.2 Non-Brownian Sedimentation, 47 4.3 Velocity Fluctuations, 48 4.3.1 Introduction, 48 Caflisch and Luke Divergence Paradox, 48 4.3.2 Thin Cells and Quasi Steady-State Sedimentation, 49 Hydrodynamic Diffusion, 51 4.3.3 Thick Cells, Time-Dependent Sedimentation, and Stratification, 52 Time-Dependent Sedimentation, 52 Stratification Scaling Model, 54 4.3.4 Stratification Model in a Fluidized Bed, 55 4.4 Summary, 56 References, 57 5 Particles in Electric Fields 59 Todd M. Squires 5.1 Electrostatics in Electrolytes, 60 5.1.1 The Poisson–Boltzmann Equation, 61 5.1.2 Assumptions Underlying the Poisson–Boltzmann Equation, 62 5.1.3 Alternate Approach: The Electrochemical Potential, 63 5.1.4 Electrokinetics, 64 5.2 The Poisson–Nernst–Planck–Stokes Equations, 65 5.3 Electro-Osmotic Flows, 66 5.3.1 Alternate Approach: The Electrochemical Potential, 67 5.4 Electrophoresis, 68 5.4.1 Electrophoresis in the Thick Double-Layer Limit, 69 5.4.2 Electrophoresis in the Thin Double-Layer Limit, 69 5.4.3 Electrophoresis for Arbitrary Charge and Screening Length, 71 5.4.4 Concentration Polarization, 72 5.5 Nonlinear Electrokinetic Effects, 75 5.5.1 Induced-Charge Electrokinetics, 75 5.5.2 Dielectrophoresis, 76 5.5.3 Particle Interactions and Electrorheological Fluids, 77 5.6 Conclusions, 77 References, 78 6 Colloidal Dispersions in Shear Flow 81 Minne P. Lettinga 6.1 Introduction, 81 6.2 Basic Concepts of Rheology, 82 6.2.1 Definition of Shear Flow, 82 6.2.2 Scaling the Shear Rate, 83 6.2.3 Flow Instabilities, 84 6.3 Effect of Shear Flow on Crystallization of Colloidal Spheres, 86 6.3.1 Equilibrium Phase Behavior, 87 6.3.2 Nonequilibrium Phase Behavior, 87 6.3.3 The Effect on Flow Behavior, 91 6.4 Effect of Shear Flow on Gas–Liquid Phase Separating Colloidal Spheres, 92 6.4.1 Equilibrium Phase Behavior, 92 6.4.2 Nonequilibrium Phase Behavior, 95 6.4.3 The Effect on Flow Behavior, 98 6.5 Effect of Shear Flow on the Isotropic–Nematic Phase Transition of Colloidal Rods, 99 6.5.1 Equilibrium Phase Behavior: Isotropic–Nematic Phase Transition from a Dynamical Viewpoint, 100 6.5.2 Nonequilibrium Phase Behavior of Sheared Rods: Theory, 102 6.5.3 Nonequilibrium Phase Behavior of Sheared Rods: Experiment, 104 6.5.4 The Effect of the Isotropic–Nematic Transition on the Flow Behavior, 107 6.6 Concluding Remarks, 108 References, 109 7 Colloidal Interactions with Optical Fields: Optical Tweezers 111 David McGloin, Craig McDonald, & Yuri Belotti 7.1 Introduction, 111 7.2 Theory, 112 7.3 Experimental Systems, 114 7.3.1 Optical Tweezers, 114 7.3.2 Force Measuring Techniques, 116 7.3.3 Radiation Pressure Traps, 120 7.3.4 Beam Shaping Techniques, 121 7.4 Applications, 122 7.4.1 Colloidal Science, 122 7.4.2 Nanoparticles, 123 7.4.3 Colloidal Aerosols, 123 7.5 Conclusions, 125 References, 125 SECTION III EXPERIMENTAL TECHNIQUES 131 8 Scattering Techniques 133 Luca Cipelletti, Véronique Trappe, & David J. Pine 8.1 Introduction, 133 8.2 Light and Other Scattering Techniques, 134 8.3 Static Light Scattering, 135 8.3.1 Static Structure Factor, 136 8.3.2 Form Factor, 137 8.4 Dynamic Light Scattering, 138 8.4.1 Conventional Dynamic Light Scattering, 138 8.4.2 Diffusing Wave Spectroscopy, 139 8.4.3 Dynamic Light Scattering from Nonergodic Media, 142 8.4.4 Multispeckle Methods, 143 8.4.5 Time-Resolved Correlation, 143 8.5 Imaging and Scattering, 145 8.5.1 Photon Correlation Imaging, 145 8.5.2 Near Field Scattering, 146 8.5.3 Differential Dynamic Microscopy, 147 References, 148 9 Rheology of Soft Materials 149 Hans M. Wyss 9.1 Introduction, 149 9.2 Deformation and Flow: Basic Concepts, 150 9.2.1 Importance of Timescales, 150 9.3 Stress Relaxation Test: Time-Dependent Response, 151 9.3.1 The Linear Response Function G(t), 152 9.4 Oscillatory Rheology: Frequency-Dependent Response, 153 9.4.1 Storage Modulus G′ and Loss Modulus G′′, 153 9.4.2 Relation Between Frequency- and Time-Dependent Measurements, 154 9.5 Steady Shear Rheology, 154 9.6 Nonlinear Rheology, 155 9.6.1 Large Amplitude Oscillatory Shear (LAOS) Measurements, 155 9.6.2 Lissajous Curves and Geometrical Interpretation of LAOS Data, 155 9.6.3 Fourier Transform Rheology, 157 9.7 Examples of Typical Rheological Behavior for Different Soft Materials, 157 9.7.1 Soft Glassy Materials, 157 9.7.2 Gel Networks, 159 9.7.3 Biopolymer Networks: Strain-Stiffening Behavior, 160 9.8 Rheometers, 160 9.8.1 Rotational Rheometers, 160 9.8.2 Measuring Geometries, 160 9.8.3 Stress- and Strain-Controlled Rheometers, 161 9.9 Conclusions, 162 References, 162 10 Optical Microscopy of Soft Matter Systems 165 Taewoo Lee, Bohdan Senyuk, Rahul P. Trivedi, & Ivan I. Smalyukh 10.1 Introduction, 165 10.2 Basics of Optical Microscopy, 166 10.3 Bright Field and Dark Field Microscopy, 167 10.4 Polarizing Microscopy, 169 10.5 Differential Interference Contrast and Phase Contrast Microscopies, 170 10.6 Fluorescence Microscopy, 171 10.7 Fluorescence Confocal Microscopy, 172 10.8 Fluorescence Confocal Polarizing Microscopy, 174 10.9 Nonlinear Optical Microscopy, 176 10.9.1 Multiphoton Excitation Fluorescence Microscopy, 176 10.9.2 Multiharmonic Generation Microscopy, 177 10.9.3 Coherent Anti-Stokes Raman Scattering Microscopy, 178 10.9.4 Coherent Anti-Stokes Raman Scattering Polarizing Microscopy, 179 10.9.5 Stimulated Raman Scattering Microscopy, 180 10.10 Three-Dimensional Localization Using Engineered Point Spread Functions, 181 10.11 Integrating Three-Dimensional Imaging Systems With Optical Tweezers, 182 10.12 Outlook and Perspectives, 183 References, 184 SECTION IV COLLOIDAL PHASES 187 11 Colloidal Fluids 189 José Luis Arauz-Lara 11.1 Introduction, 189 11.2 Quasi-Two-Dimensional Colloidal Fluids, 190 11.3 Static Structure, 190 11.4 Model Pair Potential, 193 11.5 The Ornstein–Zernike Equation, 195 11.6 Static Structure Factor, 196 11.7 Self-Diffusion, 197 11.8 Dynamic Structure, 198 11.9 Conclusions, 200 Acknowledgments, 200 References, 200 12 Colloidal Crystallization 203 Zhengdong Cheng 12.1 Crystallization and Close Packing, 203 12.1.1 van der Waals Equation of State and Hard Spheres as Model for Simple Fluids, 204 12.1.2 The Realization of Colloidal Hard Spheres, 205 12.2 Crystallization of Hard Spheres, 208 12.2.1 Phase Behavior, 208 12.2.2 Equation of State of Hard Spheres, 210 12.2.3 Crystal Structures, 215 12.2.4 Crystallization Kinetics, 218 12.3 Crystallization of Charged Spheres, 229 12.3.1 Phase Behavior, 229 12.3.2 Crystallization Kinetics, 235 12.4 Crystallization of Microgel Particles, 237 12.4.1 Phase Behavior, 238 12.4.2 Crystallization and Melting Kinetics, 238 12.5 Conclusions and New Directions, 241 Acknowledgments, 242 References, 242 13 The Glass Transition 249 Johan Mattsson 13.1 Introduction, 249 13.2 Basics of Glass Formation, 250 13.2.1 Basics of Glass Formation in Molecular Systems, 250 13.2.2 Basics of Glass Formation in Colloidal Systems, 252 13.3 Structure of Molecular or Colloidal Glass-Forming Systems, 252 13.4 Dynamics of Glass-Forming Molecular Systems, 254 13.4.1 Relaxation Dynamics as Manifested in the Time Domain, 254 13.4.2 Relaxation Dynamics as Manifested in the Frequency Domain, 256 13.4.3 The Structural Relaxation Time, 258 13.4.4 The Stretching of the Structural Relaxation, 259 13.4.5 The Dynamic Crossover, 259 13.5 Dynamics of Glass-Forming Colloidal Systems, 262 13.5.1 General Behavior, 262 13.5.2 The Structural Relaxation, 263 13.5.3 The Dynamic Crossover, 264 13.5.4 “Fragility” in Colloidal Systems, 265 13.5.5 Glassy “Secondary” Relaxations, 266 13.6 Further Comparisons Between Molecular and Colloidal Glass Formation, 267 13.6.1 Dynamic Heterogeneity, 267 13.6.2 Decoupling of Translational and Rotational Diffusion, 269 13.6.3 The Vibrational Properties and the Boson Peak, 270 13.7 Theoretical Approaches to Understand Glass Formation, 271 13.7.1 Above the Dynamic Crossover: Mode Coupling Theory, 271 13.7.2 Below the Dynamic Crossover: Activated Dynamics, 273 13.8 Conclusions, 275 References, 276 14 Colloidal Gelation 279 Emanuela Del Gado, Davide Fiocco, Giuseppe Foffi, Suliana Manley, Veronique Trappe, & Alessio Zaccone 14.1 Introduction: What Is a Gel? 279 14.1.1 An Experimental Summary: How Is a Gel Made? 280 14.2 Colloid Interactions: Two Important Cases, 280 14.2.1 “Strong” Interactions: van der Waals Forces, 280 14.2.2 “Weak” Interactions: Depletion Interactions, 282 14.2.3 Putting It All Together, 285 14.3 Routes to Gelation, 285 14.3.1 Dynamic Scaling, 285 14.3.2 Fractal Aggregation, 287 14.4 Elasticity of Colloidal Gels, 288 14.4.1 Elasticity of Fractal Gels, 288 14.4.2 Deformations and Connectivity, 289 14.5 Conclusions, 290 References, 290 SECTION V OTHER SOFT MATERIALS 293 15 Emulsions 295 Sudeep K. Dutta, Elizabeth Knowlton, & Daniel L. Blair 15.1 Introduction, 295 15.1.1 Background, 295 15.2 Processing and Purification, 296 15.2.1 Creation and Stability, 296 15.2.2 Destabilization and Aggregation, 298 15.2.3 Coarsening, 298 15.2.4 Purification: Creaming and Depletion, 299 15.3 Emulsion Science, 300 15.3.1 Microfluidics: Emulsions on a Chip, 300 15.3.2 Dense Emulsions and Jamming, 300 15.3.3 The Jammed State, 301 15.3.4 The Flowing State, 304 15.4 Conclusions, 305 References, 305 16 An Introduction to the Physics of Liquid Crystals 307 Jan P. F. Lagerwall 16.1 Overview of This Chapter, 307 16.2 Liquid Crystal Classes and Phases, 308 16.2.1 The Foundations: Long-Range Order, the Nematic Phase, and the Director Concept, 308 16.2.2 Thermotropics and Lyotropics: The Two Liquid Crystal Classes, 308 16.2.3 The Smectic and Lamellar Phases, 311 16.2.4 The Columnar Phases, 313 16.2.5 Chiral Liquid Crystal Phases, 314 16.2.6 Liquid Crystal Polymorphism, 316 16.3 The Anisotropic Physical Properties of Liquid Crystals, 317 16.3.1 The Orientational Order Parameter, 317 16.3.2 Optical Anisotropy, 318 16.3.3 Dielectric, Conductive, and Magnetic Anisotropy and the Response to Electric and Magnetic Fields, 321 16.3.4 The Viscous Properties of Liquid Crystals, 323 16.4 Deformations and Singularities in The Director Field, 325 16.4.1 Liquid Crystal Elasticity, 325 16.4.2 The Characteristic Topological Defects of Liquid Crystals, 327 16.5 The Special Physical Properties of Chiral Liquid Crystals, 330 16.5.1 Optical Activity and Selective Reflection, 330 16.6 Some Examples From Present-Day Liquid Crystal Research, 332 16.6.1 Colloid Particles in Liquid Crystals and Liquid Crystalline Colloid Particles, 333 16.6.2 Biodetection with Liquid Crystals, 333 16.6.3 Templating and Nano-/Microstructuring Using Liquid Crystals, 334 16.6.4 Liquid Crystals for Photovoltaic and Electromechanical Energy Conversion, 334 16.6.5 Lipidomics and the Liquid Crystal Phases of Cell Membranes, 336 16.6.6 Active Nematics, 336 References, 336 17 Entangled Granular Media 341 Nick Gravish & Daniel I. Goldman 17.1 Granular Materials, 342 17.1.1 Dry, Convex Particles, 342 17.1.2 Cohesion through Fluids, 343 17.1.3 Cohesion through Shape, 343 17.1.4 Characterize the Rheology of Granular Materials, 344 17.2 Experiment, 345 17.2.1 Experimental Apparatus, 345 17.2.2 Packing Experiments, 346 17.2.3 Collapse Experiments, 346 17.3 Simulation, 348 17.3.1 Random Contact Model of Rods, 348 17.3.2 Packing Simulations, 350 17.4 Conclusions, 352 Acknowledgments, 352 References, 352 18 Foams 355 Reinhard Ḧohler & Sylvie Cohen-Addad 18.1 Introduction, 355 18.2 Equilibrium Structures, 356 18.2.1 Equilibrium Conditions, 356 18.2.2 Geometrical and Topological Properties, 358 18.2.3 Static Bubble Interactions, 358 18.3 Aging, 359 18.3.1 Drainage, 359 18.3.2 Coarsening, 360 18.3.3 Coalescence, 361 18.4 Rheology, 361 18.4.1 Elastic Response, 361 18.4.2 Linear Viscoelasticity, 362 18.4.3 Yielding and Plastic Flow, 363 18.4.4 Viscous Flow, 364 18.4.5 Rheology near the Jamming Transition, 365 References, 366 SECTION VI ORDERED MATERIALS IN CURVED SPACES 369 19 Crystals and Liquid Crystals Confined to Curved Geometries 371 Vinzenz Koning, & Vincenzo Vitelli 19.1 Introduction, 371 19.2 Crystalline Solids and Liquid Crystals, 373 19.3 Differential Geometry of Surfaces, 373 19.3.1 Preliminaries, 373 19.3.2 Curvature, 374 19.3.3 Monge Gauge, 375 19.4 Elasticity on Curved Surfaces and in Confined Geometries, 375 19.4.1 Elasticity of a Two-Dimensional Nematic Liquid Crystal, 375 19.4.2 Elasticity of a Two-Dimensional Solid, 376 19.4.3 Elasticity of a Three-dimensional Nematic Liquid Crystal, 377 19.5 Topological Defects, 377 19.5.1 Disclinations in a Nematic, 377 19.5.2 Disclinations in a Crystal, 378 19.5.3 Dislocations, 378 19.6 Interaction Between Curvature and Defects, 379 19.6.1 Coupling in Liquid Crystals, 379 19.6.2 Coupling in Crystals, 379 19.6.3 Screening by Dislocations and Pleats, 381 19.6.4 Geometrical Potentials and Forces, 381 19.7 Nematics in Spherical Geometries, 381 19.7.1 Nematic Order on the Sphere, 381 19.7.2 Beyond Two Dimensions: Spherical Nematic Shells, 382 19.8 Toroidal Nematics, 383 19.9 Concluding Remarks, 383 References, 383 20 Nematics on Curved Surfaces – Computer Simulations of Nematic Shells 387 Martin Bates 20.1 Introduction, 387 20.2 Theory, 388 20.3 Experiments on Spherical Shells, 389 20.3.1 Nematics, 389 20.3.2 Smectics, 391 20.4 Computer Simulations – Practicalities, 392 20.4.1 Introduction, 392 20.4.2 Monte Carlo Simulations, 393 20.5 Computer Simulations of Nematic Shells, 395 20.5.1 Spherical Shells, 395 20.5.2 Nonspherical Shells, 397 20.6 Conclusions, 399 References, 401 Index 403

About the Author :
Alberto Fernandez-Nieves received his Ph.D. in Physics from the University of Granada and is Assistant Professor of Physics at the Georgia Institute of Technology. Before joining GeorgiaTech, he was Lecturer of Physics at the University of Almeria and studies the physics of soft materials with a focus on the connection between microscopic order and macroscopic properties.