Freezing Colloids: Observations, Principles, Control, and Use (eBook)

Dr. Sylvain Deville is currently a researcher at the CNRS in France and has worked in the field of materials science for 15 years. Since 2004, he has worked extensively on the freezing of colloids and its application in processing advanced, bioinspired materials. He has published over 60 papers in refereed international journals and holds 7 patents. In 2012, he was awarded the bronze medal by the CNRS for his research achievements in freezing colloids, and he received a European Research Council (ERC) starting grant on the same topic. His current interests include the various occurrences of colloid freezing and their applications in fields as diverse as materials science, geophysics, and biology.

Preface 7
Acknowledgements 10
Contents 11
Acronyms 18
1 Freezing Colloids: Natural and Technological Occurrences 21
1.1 The Small World of Colloids 21
1.2 Sea Ice 23
1.2.1 Brine Channels 23
1.2.2 Sea Ice and the Emergence of Life on Earth 25
1.3 Frost Heave 26
1.4 Life and Liquid Water on Mars 30
1.5 Biology 32
1.5.1 Cryosurgery 33
1.5.2 Cryopreservation of Cells and Tissues 35
1.5.3 Freezing Resistance of Organisms 38
1.6 Food Engineering 42
1.6.1 Cryopreservation of Food 42
1.6.2 Frozen Dessert and Ice Cream 43
1.7 Engineering 45
1.7.1 Water Treatment 45
1.7.2 Desalination 48
1.8 Civil Engineering 52
1.9 Materials Science 53
1.9.1 Metallurgy 55
1.9.2 Ice-Templating, Freeze-Casting 59
1.9.3 Paint 61
1.10 Conclusions 63
References 63
2 Investigating the Freezing of Colloids: Experimental Techniques to Probe Solidification Patterns, Crystal Growth, and Particle Movement 67
2.1 What Are We Looking For? 67
2.2 Time and Space Scales 69
2.3 Solidification Patterns 72
2.3.1 Field Observations 72
2.3.2 Optical Microscopy 72
2.3.3 Scanning Electron Microscopy 78
2.3.4 Magnetic Resonance Imaging 80
2.3.5 Near-Infrared Imaging Spectroscopy 81
2.3.6 Cryomicroscopy 81
2.4 Crystal Growth: Kinetics, Shape, Crystalline Structure 83
2.4.1 Optical Interferometry 84
2.4.2 X-Ray Imaging 85
2.4.3 Confocal Microscopy 89
2.4.4 Transmission Electron Microscopy 93
2.4.5 Electron Backscattered Diffraction 93
2.4.6 X-Ray Diffraction 96
2.5 Particle Behaviour 99
2.5.1 Force Measurements 99
2.5.2 X-Ray Scattering and Spectroscopy Techniques 102
2.6 Thermal Measurements 104
2.7 Conclusions 106
References 107
3 Understanding the Freezing of Colloidal Suspensions: Crystal Growth and Particle Redistribution 111
3.1 Nucleation and Growth 113
3.1.1 Freezing Point 113
3.1.2 Homogeneous Nucleation 114
3.1.3 Heterogeneous Nucleation 115
3.1.4 Nucleation and Supercooling 117
3.1.5 Experimental Measures of the Freezing Point 117
3.1.6 Transient Regime 118
3.1.7 Role of the Temperature Distribution and Boundary Conditions 121
3.2 The Water/Ice Interface 122
3.2.1 Nature of the Water/Ice Interface 122
3.2.2 Freezing Potential 122
3.2.3 Stresses Developed During Freezing 124
3.3 Steady State 125
3.3.1 Freeze Front Velocity 125
3.3.2 Morphology of the Interface 128
3.3.3 Faceted or Dendritic? 129
3.3.4 Confined Solidification 131
3.3.5 Solidification Patterns and Their Periodicity 132
3.3.6 Crystallographic Orientation of the Crystals 137
3.3.7 Instabilities in Steady State 140
3.4 Orientation Domains 144
3.5 Ice Lenses 146
3.5.1 Formation of Ice Lenses 147
3.5.2 Consequences of Ice Lens Formation 150
3.6 Particle Redistribution 152
3.6.1 Sedimentation 152
3.6.2 Parallel Between Freezing and Drying 153
3.6.3 Isolated Particles in Dilute Suspensions 155
3.6.4 Concentrated Suspensions 164
3.6.5 Osmotic Pressure and Particle Packing 165
3.6.6 Soft Objects 166
3.6.7 Dynamics of Particle Redistribution 172
3.7 Packing of Particles in the Frozen Structure 174
3.7.1 Monodisperse, Isotropic Particles 175
3.7.2 Polydisperse, Isotropic Particles 178
3.7.3 Anisotropic Particles 179
3.7.4 Recrystallisation of the Frozen Structure 179
3.8 The Different Modelling Approaches 182
3.9 Conclusions 184
References 185
4 Ice-Templating: Processing Routes, Architectures, and Microstructures 191
4.1 Templating Porosity with Ice Crystals: A Brief History 191
4.1.1 Early Observations 192
4.1.2 Freezing in Biology 196
4.1.3 Freezing-Induced Damages in Industrial Applications 198
4.1.4 Freezing as a Templating Route 198
4.2 Processing and Shaping Routes 202
4.2.1 Control of the Freezing Conditions 202
4.2.2 Freeze Tape-Casting 204
4.2.3 Ice-Templated Thin Films and Membranes 208
4.2.4 Assembly of Independently Frozen Pieces 212
4.2.5 Extrusion and Co-extrusion 212
4.2.6 Rapid Freezing for Nanofibres Production 216
4.2.7 Post-freezing Treatments 216
4.2.8 Emulsions 217
4.3 Microstructures and Architectures 217
4.3.1 Orientation Domains of Crystals 218
4.3.2 Macroporosity 224
4.3.3 Meso and Microporosity 236
4.3.4 Aerogels 244
4.3.5 Fibres 248
4.3.6 Microparticles 252
4.4 Reproducibility 257
4.5 Conclusions 259
References 260
5 Ice-Templated Materials: Polymers, Ceramics, Metals and Their Composites 273
5.1 Dense Ceramics 273
5.2 Porous Ceramics 274
5.2.1 Materials 275
5.2.2 Processing 293
5.3 Glasses 297
5.4 Polymers 300
5.4.1 Materials and Applications 300
5.4.2 Solvents 303
5.4.3 Process 304
5.5 Preceramics Polymers 306
5.6 Metals 308
5.6.1 From Metal Particles 308
5.6.2 From Precursors 311
5.6.3 Solvents 314
5.7 Cryogels 315
5.8 Carbon Materials 319
5.9 Porous Composites 324
5.9.1 Ceramic/Polymer Porous Composites 324
5.9.2 Ceramic/Ceramic Porous Composites 328
5.9.3 Polymer/Polymer Porous Composites 331
5.9.4 Carbon-Based Porous Composites 332
5.9.5 Other Porous Composites 335
5.10 Dense Composites 336
5.10.1 Metal/ceramic Composites 337
5.10.2 Polymer/ceramic Composites 340
5.10.3 Ceramic/ceramic Composites 341
5.11 Conclusions 342
References 343
6 Ice-Templating and Freeze-Casting: Control of the Processes, Microstructures, and Architectures 371
6.1 Preparation of the Colloidal Suspensions 371
6.1.1 Solvent 371
6.1.2 Particles and Colloids 381
6.1.3 Formulation and Stability of the Suspensions 391
6.1.4 Foaming 395
6.1.5 Emulsions 396
6.1.6 Additives and Control of Crystal Growth 398
6.2 Towards a Control of Crystal Growth at the Atomic Level 402
6.2.1 Freeze-Tolerant Organisms 403
6.2.2 Zirconium Acetate: A Different Ice-Shaping Compound 403
6.2.3 Learning from Snowflakes 405
6.3 Control of the Freezing Conditions 406
6.3.1 Evaporation 406
6.3.2 Nucleation and Growth 408
6.3.3 Design of the Mould 412
6.3.4 Directionality and Magnitude of the Temperature Gradient 413
6.3.5 Cooling Rate 421
6.3.6 Freezing in a Template 428
6.3.7 Pre-made Ice Templates 429
6.3.8 Two-Step Freezing 432
6.3.9 Two-Dimensional Ice-Templating 433
6.3.10 Application of External Fields 434
6.4 Recrystallisation 438
6.5 Sublimation 441
6.6 Multiple Freeze--Thaw Cycles 444
6.7 Conclusions 447
References 447
7 Properties and Applications of Ice-Templated Materials 459
7.1 What is the Interest of Ice-Templated Materials? 459
7.2 Reporting of the Results 461
7.3 Anisotropy of Properties 462
7.4 Physical Properties 463
7.4.1 Porosity 463
7.4.2 Density 468
7.4.3 Specific Surface Area 468
7.4.4 Permeability 469
7.4.5 Conductivity and Resistivity 477
7.4.6 Dielectric Properties 478
7.4.7 Piezoelectric Properties 480
7.4.8 Thermal Properties 483
7.4.9 Capacitance 484
7.4.10 Permittivity 487
7.4.11 Other Physical Properties 488
7.5 Structural Properties 488
7.5.1 Compressive Strength 488
7.5.2 Reliability 505
7.5.3 Flexural Strength 507
7.5.4 Young's Modulus 508
7.5.5 Toughness 509
7.6 Functional Properties 514
7.6.1 Catalytic Properties 514
7.6.2 Acoustic Properties 515
7.6.3 Corrosion Resistance 516
7.7 Applications 517
7.7.1 Armour and Impact Resistance 517
7.7.2 Biomedical Applications 517
7.7.3 Membranes 526
7.7.4 Adsorption and Depollution 528
7.7.5 Antifungal Properties 530
7.7.6 Electrochemical Cells 530
7.7.7 Batteries, Capacitors, and Supercapacitors 532
7.7.8 Sensors 534
7.7.9 Field Emitters 534
7.7.10 Solar Cells 535
7.7.11 Thermal Insulation 536
7.7.12 Thermoresponsive Materials 536
7.7.13 Shape Memory Materials 537
7.7.14 Thermal Energy Storage 538
7.7.15 Phase Change Heat Transfer 540
7.7.16 Food Engineering 540
7.7.17 Plasmonic Materials 541
7.7.18 Antibacterial Material 541
7.7.19 Chemical Reactions 541
7.7.20 Model Materials for Physical Studies 544
7.8 Conclusions: What's Next? 545
7.8.1 Why Freezing? 546
7.8.2 Towards Commercial Products? 546
References 548
8 Ice-Templating, Freeze-Casting: A Practical Guide to Get Started 569
8.1 What Do You Want to Do? 569
8.2 Your Budget 570
8.3 Materials 571
8.3.1 Samples Dimensions 576
8.3.2 Required Cooling Rate 576
8.4 Freezing 577
8.4.1 Moulds 577
8.4.2 Which Coolant? 577
8.4.3 EHS with Liquid Nitrogen 579
8.4.4 Freezing Directionality 580
8.4.5 Directional Freezing 581
8.4.6 Extracting the Sample from the Mould 586
8.5 Freeze-Drying 587
8.5.1 Protecting Your Pump from Solvents 589
8.5.2 Sample Preparation 589
8.6 Observing Samples 590
8.6.1 Describing the Structure 590
8.6.2 Mercury Porosimetry 591
8.6.3 Image Analysis in 2D and 3D 592
8.7 Troubleshooting 595
8.7.1 My Pores Are Too Large! 595
8.7.2 My Pores Are Too Small! 596
8.7.3 The Strength of My Samples Is Too Low! 597
8.7.4 I Have Defects in the Structure! 598
8.8 Final Words 603
References 604
Index 613