With 16 chapters from world-renowned researchers, this book offers an extraordinary commentary on the burgeoning current research activity in contact angle and wettability
The present volume constitutes Volume 3 in the ongoing series Advances in Contact Angle, Wettability and Adhesion which was conceived with the intent to provide periodic updates on the research activity and salient developments in the fascinating arena of contact angle, wettability and adhesion.
The book is divided into four parts: Part 1: Contact Angle Measurement and Analysis; Part 2: Wettability Behavior; Part 3: Superhydrophobic Surfaces; Part 4: Wettability, Surface Free Energy and Adhesion. The topics covered include: procedure to measure and analyse contact angle/drop shape behaviors; contact angle measurement considering spreading, evaporation and reactive substrate; measurement of contact angle of a liquid on a substrate of the same liquid; evolution of axisymmetric droplet shape parameters; interfacial modulus of a solid surface; functionalization of textiles using UV-based techniques for surface modification--patterned wetting behavior; wettability behavior of oleophilic and oleophobic nanorough surfaces; wettability behavior of nanofluids; dielectrowetting for digital microfluidics; hydrophobicity and superhydrophobicity in fouling prevention; superhydrophobic/superhydrophilic hybrid surface; determination of the surface free energy of solid surfaces: statistical considerations; determination of apparent surface free energy using hysteresis approach; wettability correlations for bioadhesion to different materials; laser material processing for enhancing stem cell adhesion and growth.
Table of Contents
Preface xv
Part 1 Contact Angle Measurement and Analysis 1
1 A More Appropriate Procedure to Measure and Analyse Contact Angles/Drop Shape Behaviours 3
M. Schmitt and F. Heib
1.1 Introduction 4
1.1.1 Brief Summary of the History of “Modern” Wetting 4
1.1.2 Vexing Question in Wettability 5
1.1.3 Background 6
1.1.3.1 Force Balance and Roughness 6
1.1.3.2 Selected Theoretical Aspects 8
1.1.3.3 Contact Angle Analysis and Hysteresis 11
1.2 Experimental 13
1.3 Obtaining “Continuous” Drop Shapes and Independent Contact Angles 14
1.3.1 HPDSA: Image Transformation 14
1.3.2 HPDSA: Contact Angle Determination 17
1.3.3 HPDSA: Triple Point Determination 20
1.3.4 HPDSA Software 21
1.3.4.1 Baseline Determination 21
1.3.4.2 Image Transformation 21
1.3.4.3 Fitting Procedure and Convergence 24
1.4 Different Contact Angles Analyses 25
1.4.1 Possible Static Analysis 25
1.4.2 Overall Contact Angle Analysis 25
1.4.2.1 Example: Inclined Plane 27
1.4.2.2 Example: Horizontal Plane with Immersed Needle 30
1.4.3 Statistical Event Analysis: Velocity and Statistical Event Definition 33
1.4.4 Statistical Event Analysis: Independent/Global Contact Angle Analysis 35
1.4.5 Statistical Event Analysis: Dependent/Individual Contact Angle Analysis 39
1.4.6 Statistical Event Analysis: Example Demonstration of Analysis Procedures 39
1.5 Summary/Outlook 44
1.5.1 Summary – Contact Angles Determination and Analyses 44
1.5.2 Outlook – Drop Shape Behaviour 46
Acknowledgements 48
Glossary of Symbols 48
Copyrights 52
References 52
2 Optical Contact Angle Measurement Considering Spreading, Evaporation and Reactive Substrate 59
Md Farhad Ismail, Aleksey Baldygin, Thomas Willers and Prashant R. Waghmare
2.1 Introduction 60
2.2 Experimental Setup for Contact Angle Measurement 64
2.2.1 Ideal Drop Spreading 65
2.2.2 Role of Environmental Condition 66
2.2.3 Ideal Environmental (Saturated Vapor) Condition 69
2.2.4 Reactive System Condition 71
2.3 Summary 74
2.4 Supplementary Media Material 75
Acknowledgement 75
References 75
3 Method Development for Measuring Contact Angles of Perfluoropolyether Liquid on Fomblin HC/25® PFPE Film 81
D. Rossi, S. Dall’Acqua, S. Rossi, M. Zancato, P. Pittia, E. Franceschinis, N. Realdon and A. Bettero
3.1 Introduction 82
3.2 Experimental 83
3.2.1 Method Used 84
3.2.2 Determination of Surface Free Energy (SFE) 86
3.2.3 Contact Angles Measurements of PFPE Drop on PFPE “Liquid Film” (PFPEd/PFPEf) 86
3.2.4 Statistical Analyses 86
3.3 Results and Discussion 87
3.3.1 Surface Free Energy (SFE) Characterization of PermaFoam 87
3.3.2 Surface Free Energy Characterization of PFPE “Liquid Film” 87
3.4 Summary 94
Acknowledgements 95
References 96
4 Characterizing the Physicochemical Processes at the Interface through Evolution of the Axisymmetric Droplet Shape Parameters 99
Ludmila Boinovich and Alexandre Emelyanenko
4.1 Introduction 99
4.2 The Relationships between the Contact Angle and the Thermodynamic and Geometric Characteristics of the Surface 100
4.3 Experimental Methods for Determination of the Contact Angle and the Surface Tension for a Sessile Droplet on the Surface 106
4.4 Determination of the Wetting Tension and the Wetted Area Fraction on the Basis of Temporal Evolution of Contact Angle and Surface Tension in Sessile Drop Method 109
4.5 Testing the Mechanical Durability of Superhydrophobic Coatings 118
4.6 Summary 124
References 125
5 The Interfacial Modulus of a Solid Surface and the Young’s Equilibrium Contact Angle Using Line Energy 131
Sakshi B. Yadav, Ratul Das, Semih Gulec, Jie Liu and Rafael Tadmor
5.1 Introduction 132
5.2 The Young Equation Obtained with a Three-Dimensional Description 134
5.3 Incorporating the Contact Line into the Young Equation 135
5.4 Finding the Young Thermodynamic Contact Angle from Advancing/Receding Data 136
5.5 Interfacial Modulus Gs Associated with the Solid Surface 138
5.6 Summary 141
References 141
Part 2 Wettability Behavior 145
6 Patterned Functionalization of Textiles Using UV-Based Techniques for Surface Modification – Patterned Wetting Behavior 147
Thomas Bahners, Thomas Mayer-Gall, Wolfgang Molter-Siemens and Jochen S. Gutmann
6.1 Introduction 148
6.2 UV-Based Processes for Surface Modification 152
6.2.1 Modifying the Surface Chemistry by Photo-Grafting 152
6.2.2 Laser-Induced Roughening of Fiber Surfaces 153
6.3 Experimental 154
6.4 Results 155
6.4.1 Lateral Wetting Patterns 155
6.4.2 Selective Wetting on Inner and Outer Surfaces 158
6.5 Summary and Outlook 160
References 161
7 Wettability Behavior of Oleophilic and Oleophobic Nanorough Surfaces in Air or Immersed in Water 167
Luisa Coriand, Nadja Felde and Angela Duparre
7.1 Introduction 167
7.2 Sample Preparation 168
7.3 Characterization Methods 169
7.3.1 Roughness 169
7.3.2 Wetting 169
7.4 Surface Roughness of Al2O3 Coatings 170
7.5 Wetting Behavior of Al2O3 Coatings 173
7.5.1 Air as Fluid Phase 173
7.5.2 Water as Fluid Phase 173
7.6 Wetting Behavior of Al2O3 Coatings Overcoated with a Thin Top Layer 174
7.6.1 Air as Fluid Phase 174
7.6.2 Water as Fluid Phase 175
7.7 Summary 177
Acknowledgements 177
References 177
8 Effect of Particle Loading and Stability on the Wetting Behavior of Nanofluids 179
A. Karthikeyan, S. Coulombe and A.M. Kietzig
8.1 Introduction 180
8.2 Review on Wetting Behavior and Stability of Nanofluids 181
8.3 Summary 186
References 188
9 Dielectrowetting for Digital Microfluidics 193
Hongyao Geng and Sung Kwon Cho
9.1 Introduction 194
9.2 Electrowetting on Dielectric (EWOD) 196
9.3 Liquid-Dielectrophoresis (L-DEP) 198
9.4 L-DEP in Microfluidics 200
9.5 Dielectrowetting 203
9.6 Droplet Manipulations by Dielectrowetting 208
9.6.1 Experimental Setup 208
9.6.2 Droplet Splitting and Transporting 209
9.6.3 Multi-Splitting and Merging of Droplets 210
9.6.4 Droplet Creating 211
9.6.5 Manipulations of Aqueous Droplets 212
9.7 Concluding Remarks and Outlook 214
References 215
Part 3 Superhydrophobic Surfaces 219
10 Development of a Superhydrophobic/Superhydrophilic Hybrid Surface by Selective Micropatterning and Electron Beam Irradiation 221
Keun Park and Hyun-Joong Lee
10.1 Introduction 222
10.2 Selective Micropatterning Using Ultrasonic Imprinting 224
10.2.1 Ultrasonic Imprinting for Micropattern Replication 224
10.2.2 Selective Ultrasonic Imprinting Using a Profiled Mask Film 225
10.2.3 Fabrication of a Micropatterned Mold 225
10.2.4 Selective Ultrasonic Imprinting for Development of Hydrophobic Micropatterns 227
10.3 Selective Wettability Control 229
10.3.1 Selective Surface Treatments 229
10.3.2 Surface Hydrophobization Using Selective Hydrophobic Silane Coating 230
10.3.3 Surface Hydrophilization Using Electron Beam Irradiation 232
10.4 Development of Hybrid Surfaces with Versatile Wettability 233
10.4.1 Investigation of Selectively Wettable Characteristics 233
10.4.2 Water Collection by the Developed Hybrid Surface 234
10.4.3 Hybrid Surface with a Combination of Three Surface Treatments 235
10.5 Summary 236
Acknowledgements 237
References 237
11 Hydrophobicity and Superhydrophobicity in Fouling Prevention in Sea Environment 241
Michele Ferrari and Francesca Cirisano
11.1 Introduction 241
11.1.1 Marine Biofouling 243
11.1.1.1 Biofouling and Inorganic Fouling 244
11.1.1.2 Colonization 245
11.1.1.3 Inorganic Fouling 246
11.1.2 Surface Features and Bioadhesion 247
11.2 Antifouling Options 248
11.3 Problem Statement 251
11.4 Coatings with Special Wettability and Performance Against Biofouling 252
11.4.1 Silane-Based Coatings 253
11.4.1.1 Hydrophobic Behaviour 253
11.4.1.2 Superhydrophobic Behaviour 255
11.4.2 Other Materials 256
11.4.2.1 Hydrophobic Behaviour 256
11.4.2.2 Superhydrophobic Behaviour 257
11.5 General Discussion 258
11.6 Summary 260
References 260
12 Superhydrophobic Surfaces for Anti-Corrosion of Aluminum 267
Junghoon Lee and Chang-Hwan Choi
12.1 Introduction 268
12.1.1 Corrosion of Metallic Materials 268
12.1.2 Surface Treatment for Anti-Corrosion of Metals 269
12.1.3 Anti-Corrosion of a Superhydrophobic Surface on Aluminum and Its Alloys 271
12.2 Fundamentals of Superhydrophobic Surface for Anti-Corrosion 273
12.2.1 Electrochemical Reactions 273
12.2.2 Wetting on Solid Surfaces 275
12.2.3 Superhydrophobic Surface for Anti-Corrosion 276
12.3 Applications of Superhydrophobized Aluminum Surfaces for Anti-corrosion 278
12.4 Summary 287
References 288
Part 4 Wettability, Surface Free Energy and Adhesion 299
13 Determination of the Surface Free Energy of Solid Surfaces: Statistical Considerations 301
Frank M. Etzler
13.1 Introduction 302
13.1.1 Neumann’s Method 302
13.1.2 van Oss, Chaudhury and Good Approach 305
13.1.3 Chen and Chang Model 308
13.1.4 The Present Work 309
13.2 Data Analysis 310
13.2.1 Data by Kwok et al. 310
13.2.1.1 Lessons from Analysis of Data by Kwok et al. 315
13.2.2 Analysis of Data by Dalal 317
13.2.3 An Alternate Experimental Approach 325
13.3 Summary and Conclusions 326
References 328
14 Equilibrium Contact Angle and Determination of Apparent Surface Free Energy Using Hysteresis Approach on Rough Surfaces 331
Konrad Terpiłowski, Diana Rymuszka, Olena Goncharuk and Lyudmyla Yakovenko
14.1 Introduction 332
14.2 Experimental 334
14.2.1 Sample Preparation 334
14.2.2 Contact Angle Measurements 335
14.2.3 Surface Free Energy Calculation 335
14.2.4 Surface Structure Characterisation 336
14.3 Results and Discussion 336
14.3.1 Contact Angles and Surface Free Energy of Sol-Gel Films 336
14.3.2 Surface Roughness and Structure of Sol-Gel Films 339
14.4 Conclusions 344
Acknowledgment 345
References 345
15 Contact Angle and Wettability Correlations for Bioadhesion to Reference Polymers, Metals, Ceramics and Tissues 349
Digvijay Singh and Robert Baier
15.1 Introduction 350
15.2 Materials and Methods 351
15.2.1 Critical Surface Tension 355
15.2.2 Calculations of Bond Strength 356
15.3 Results 357
15.3.1 Tissue Testing 357
15.4 Discussion 358
15.4.1 Regression Analysis 358
15.4.1.1 Regression Analysis for Reference Materials (Without Pyrolytic Carbon and 316 LSS) 362
15.4.2 Remaining Concerns 364
15.4.2.1 The Peculiar Case of Pyrolytic Carbon 364
15.4.2.2 The Case of Ti Alloy and 316 LSS 367
15.5 Summary and Conclusions 367
15.5.1 Limitations 369
15.6 Future Scope 369
References 370
16 The Efficacy of Laser Material Processing for Enhancing Stem Cell Adhesion and Growth on Different Materials 373
D.G. Waugh and J. Lawrence
16.1 Introduction 374
16.2 Surface Engineering Techniques in Stem Cell Technologies 376
16.2.1 Laser Surface Engineering 376
16.2.2 Plasma Surface Engineering 377
16.2.3 Lithography Techniques 377
16.2.4 Micro- and Nano-Printing 377
16.3 Laser Surface Engineering of Polymeric Materials 378
16.3.1 Experimental Technique 378
16.3.1.1 Materials 378
16.3.1.2 Laser Surface Engineering Techniques 378
16.3.1.3 Analytical Techniques 378
16.3.1.4 Biological Analysis Techniques 379
16.3.2 Effects of Laser Surface Engineering on Surface Topography 380
16.3.3 Effects of Laser Surface Engineering of Polymeric Materials on Stem Cell Adhesion and Growth 382
16.4 Laser Welding of NiTi Alloys 385
16.4.1 Experimental Technique 385
16.4.1.1 Material 385
16.4.1.2 Laser Micro-Welding Technique 385
16.4.1.3 Analytical and Biological Analysis Techniques 385
16.4.2 Surface Chemistry of Laser Micro-Welded NiTi Alloys 387
16.4.3 Effects of Laser Welding of NiTi Alloy on Stem Cell Adhesion and Growth 387
16.5 Summary and Future Considerations 390
References 392
Index 399
