Advances in Contact Angle, Wettability and Adhesion, Volume 3

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