Preface xiii
Acknowledgments xv
1 Wetting-Controlled Systems of Biological Surfaces 1
1.1 Introduction 1
1.1.1 Duck Feather 1
1.1.2 Insect Wings 3
1.1.3 Lotus Leaf 3
1.1.4 Beetle Back 4
1.1.5 Rice Leaf 4
1.1.6 Water Strider 4
1.1.7 Butterfly Wing 4
1.1.8 Mosquito Eye 5
1.1.9 Rose Petal 5
1.1.10 Fish Scale 5
1.1.11 Cicada Wing 6
1.1.12 Spider Silk 6
1.1.13 Salvinia 6
1.1.14 Cacti 7
1.1.15 Gecko Skin 7
1.1.16 Nepenthes 7
1.2 Wetting Features of Biological Surfaces 8
1.2.1 Wet-Rebuilt Spindle-Knot with Nanofibrils on Spider Silk 8
1.2.2 Slippery in Multiorder Ridges on Peristome Surface of Nepenthes 10
1.2.3 Selectively Directional Ratchet Transport 12
1.2.4 Multilevel Structured System of Cacti 13
1.2.5 Overlapping Arrangement of Fish Scale 14
1.3 Antiwetting Features of Biological Surfaces 16
1.3.1 Multilevel Wetting-Controlling on Duck Feather 16
1.3.2 Gradient Micro- and Nanostructures for Droplet Suspending-up 18
1.3.3 Oriented Microhair with Nanogroove for Superhdyrophobic Floating 20
1.3.4 Butterfly Wing with Multilevel-oriented Structures 21
1.4 Biological Patterns on Micro- and Nanoscale Structures 23
1.4.1 Isotropic Micro- and Nanostructured Pattern 24
1.4.2 Anisotropic Pattern for Wetting Direction 25
1.4.3 Alternative Hydrophilic–Hydrophobic Patterns 26
1.5 Wetting-Controlled Effects 27
1.5.1 Spider Silk Effect: Cooperative Effect of Roughness and Curvature 28
1.5.2 Cactus Effect: Cooperative Effect of Multilevel Conical Geometries 29
1.5.3 Araucaria Leaf Effect: Steering Effect of Asymmetric Capillary Ratchet Geometries 30
1.5.4 Beetle Back Effect: Hydrophilic–Hydrophobic Heterogeneous Pattern 31
1.5.5 Self-Propelling Effect: Ultrasuperhydrophobic Micro- and Nanostructures 32
1.5.6 Janus Effect of Antifreeze Proteins: Controlling Ice Formation 34
References 36
2 Mechanism and Theory of Wetting-Controlled Surfaces 41
2.1 Concept of Wetting-Controlled Effects 41
2.1.1 Wetting and Significance 41
2.1.2 Basic Definition of Wetting 42
2.1.3 Wetting in Biological Systems 44
2.1.4 Technological Relevance of Wetting Control 47
2.2 Wetting Theory of Surfaces 48
2.2.1 Fundamental Wetting Theories 48
2.2.2 Extension and Theoretical Models 49
2.2.3 Wetting Dynamics and Kinetics 51
2.2.4 Surface Roughness and Wetting 52
2.2.5 Wetting Transitions and Behavior 53
2.3 Physics of Wetting 55
2.3.1 Molecular Interactions in Wetting and Adhesion 55
2.3.2 Wetting Properties and Adhesion 56
2.3.3 Biological Structures and Adhesion Models 58
2.3.4 Quantitative Analysis of Wetting 59
2.3.5 Wetting Under External Influences 63
2.4 Surface Chemistry and Structures 64
2.4.1 Chemical Composition and Wetting 64
2.4.2 Surface Topography and Wetting Behavior 65
2.4.3 Chemical Modifications for Wetting Control 66
2.4.4 Chemical Heterogeneity and Janus 68
2.4.5 Chemistry Gradient for Controlling Wetting 70
2.5 Bioinspired Wetting-Controlled Mechanism 73
2.5.1 Liquid-Repellent Effects 73
2.5.2 Liquid Unidirection–Transport Effects 75
2.5.3 Controlling Ice Effects 76
2.5.4 Atmospheric Water Capture Effects 78
2.6 Self-Propelling Effects of Surfaces 82
2.6.1 Natural Self-Propelling System 82
2.6.2 Self-Propelling Theory from Gradient Surfaces 84
2.6.3 Self-Propelling Controlled on Conical-Structured Surfaces 85
2.6.4 Self-Propelled Droplet Jumping on Wetting-Stated Surfaces 88
2.6.5 Self-Propelled Topological Liquid Diode 89
2.7 Capillary Regime 92
2.7.1 Introduction of Capillary 92
2.7.2 Bioinspired Structured Surfaces with Controlled Capillary Rise 94
2.7.3 Rough Capillary Rise: Dual-Rise Model 95
2.7.4 Capillary Force-Induced Driving Strategy for Separations 97
2.7.5 Capillary Microfluidics System 100
2.7.6 Capillary Solar Evaporator 103
2.8 Liquid Infused Surfaces 105
2.8.1 Liquid-Infused Regulation 105
2.8.2 Bioinspired Lubricated Slippery Magnetic Responsive Array 107
2.8.3 Slippery Surface for Defensive-Offensive Antifouling 110
2.8.4 Slippery Liquid-Infused Surface for Integrative Functions 111
References 115
3 Design on Surfaces with Wetting-Controlled Effects 127
3.1 Concept of Gradients 127
3.1.1 Static Gradients 127
3.1.2 Dynamic Gradients 130
3.2 Chemistry Gradient 130
3.2.1 Gradient of Chemical Groups in Density 131
3.2.2 Molecule Gradient 131
3.2.3 Dual Gradient in Janus Wettability 133
3.2.4 Gradient in Thickness of Membrane 135
3.2.5 Gradients of Polymer Brushes 136
3.3 Texture Gradients 137
3.3.1 Anisotropic Texture Gradient 137
3.3.2 Texture Gradient of Wetting Heterogeneity 137
3.3.3 Texture Gradient of Wetting-Controlling 138
3.3.4 Texture with Gradient Polymers 140
3.4 Geometry Gradient 142
3.4.1 Spine with Microbarbs and Channels 142
3.4.2 Wedged-Induced Gradient 143
3.4.3 Conical-Induced Gradient for Wetting-Controlling 144
3.4.4 Helical-Induced Gradient 147
3.4.5 Spine-Shaped Gradient 148
3.5 Synergism of Multi-gradients 150
3.5.1 Rough Spindle-Knot for Photocatalyst 150
3.5.2 Liquid-Infused Spindle-Knot 151
3.5.3 Composite Wettability Gradient 154
3.5.4 Wettability Gradient-Induced Diode 155
3.5.5 Electronic Skin with Dual-Gradient Wettability 157
3.6 Surface Tension Gradient 159
3.6.1 Definition of Surface Tension Gradient 159
3.6.2 Asymmetric Tube to Control Surface Tension 160
3.6.3 Shape Shifting of Surface Tension and Capillary 162
3.6.4 Wettability Gradient in Cross-thickness 164
References 166
4 Development of Bioinspired Fabrication and Methods 175
4.1 Rayleigh Instability 175
4.1.1 Formation of Rayleigh Instability 175
4.1.2 Controlling of Rayleigh Instability 177
4.1.3 Bioinspired Effects of Rayleigh Instability 178
4.2 Microfluidics 179
4.2.1 Introduction of Microfluidics 179
4.2.2 Multiphase Microfluidics 181
4.2.3 Coaxial Capillary Microfluidic 182
4.2.4 Parallel-Nozzles Microfluidic 183
4.2.5 Co-Axial Microfluidic 184
4.3 Fluid-Coating 184
4.3.1 Origin of Fluid-Coating 185
4.3.2 Velocity-Regulated Fluid-Coating 187
4.3.3 Fluid-Coating for Composite Nanofibers 188
4.4 Electrospinning 189
4.4.1 Basics of Electrospinning 189
4.4.2 Bioinspired Lotus-like Structures 190
4.4.3 Bioinspoired Heterostructured Fibers 191
4.4.4 Wet Adhesive with Supercold Tolerance 193
4.4.5 Omniadhesive Fibers 194
4.4.6 Composite Nanofibrils 195
4.5 Electrochemistry 197
4.5.1 Wettable Gradient Pattern 197
4.5.2 Multiinspired 3D Wettable Gradient 198
4.5.3 Bidirectional Microchannel-Connected Pattern 199
4.5.4 Capillarity-Induced Oxidation 200
4.5.5 Bipolar Electrochemistry 201
4.6 Fluid Diffusion for Gradient 202
4.6.1 Liquid-Confined Modification for Janus Wire 204
4.6.2 Ethanol-Infused Nanofibrils Wire for Cutting Droplet 205
4.7 Laser Techniques 205
4.7.1 Laser-Fabricated Geometric Gradient Surfaces 207
4.7.2 Laser Microfabrication Strategy 207
4.7.3 Laser Ablation for Wettability Pattern 211
4.8 Printing Techniques 211
4.8.1 Introduction to Printing Techniques 213
4.8.2 Principle of Fabrication from Printings 214
4.8.3 Heterostructure Patterning on Printed Matrix 215
4.8.4 Printed Divisional Optical Biochip 215
4.9 Nanotechnology 218
4.9.1 Superhydrophilic Photothermic Nanocapsule 218
4.9.2 Photothermal Dual-Nanoscale Effect 219
4.9.3 MOF-Based Nanostructure 220
4.9.4 MOF-Composite Nanofibers 221
4.10 Plasma Techniques 222
4.10.1 Functionalities of Titania Nanotube Arrays 223
4.10.2 Pattern Fabrication in Wetting-Enabled-Transfer Strategy 224
References 226
5 Wetting-Controlled Effects for Functions and Applications 235
5.1 Condensate Droplet Transport 235
5.1.1 Coalesced-Droplet Vertical Transport 235
5.1.2 Hierarchical Droplet Size-Effect 236
5.1.3 Coalesced-Droplet Self-Propelling 237
5.2 Fog Droplet Harvesting 238
5.2.1 Introduction of Bioinspired Fog Harvesting 239
5.2.2 Thermodynamical Fog Harvesting 240
5.2.3 Janus-Integrated Fog Harvesting 241
5.3 Atmospheric Water Harvesting 244
5.3.1 MOF-Composite Nanofibers Textures 244
5.3.2 MOF-Based Polymer Composite 245
5.3.3 Super-hydrophilic Photothermic Nanocapsule 247
5.4 Anti-icing 248
5.4.1 Anti-icing onto Wind Turbine Blades 248
5.4.2 Robust Photothermal Icephobic Surface 249
5.4.3 Ice Inhibition for Cryopreservation 251
5.5 Liquid Repellency 252
5.5.1 Dually-Mobile Super-Repellency 252
5.5.2 Multi-liquid Repellency 254
5.5.3 Switchable Repellency in Both Air and Liquid 254
5.6 Energy Harvesting 256
5.6.1 Photothermal Energy Storage 256
5.6.2 Salinity-Gradient Energy Harvesting 257
5.6.3 Moisture-Driven Energy Generation 260
5.7 Heat Transfer 261
5.7.1 Thermal Energy Regulation and Utilization 261
5.7.2 Switchable Thermoregulation 263
5.7.3 Radiative Cooling Regulation 267
5.8 Artificial Skin and Sensor 268
5.8.1 Skin-Inspired Devices 268
5.8.2 Artificial Skin Vision by Wet-Infused State 269
5.8.3 Bioinspired Ionic Skins 271
5.9 Medical Application 272
5.9.1 Directional-Controllable Drug Delivery 272
5.9.2 Nature-Inspired Wet Drug Delivery 273
5.9.3 Inspired Active Injection Drug Delivery 274
References 276
Summary 293
Index 295
