Fundamentals of Adhesion

Fundamentals of Adhesion

Edited by

Lieng-Huang Lee Xerox Corporation Webster, New York

Springer Science+Business Media, LLC

Library of Congress Cataloging-in-Publication Data

Fundamentals of adhesion / edited by Lieng-Huang Lee. p. era.

Includes bibliographical references and indexes. ISBN 978-1-4899-2075-1 1. Adhesion. I. Lee, Lieng-Huang, date.

QC183.F88 1991 541.3'3--dc20 90-15509

CIP

10 9 8 7 6 5 4 3

ISBN 978-1-4899-2075-1 ISBN 978-1-4899-2073-7 (eBook) DOI 10.1007/978-1-4899-2073-7

© 1991 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1991 Softcover reprint of the hardcover 1st edition 1991

All rights reserved

No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher

Contributors

John E. E. BagHn • IBM Almaden Research Center, San Jose, California 95120-6099

Robert E. Baier • IndustrylUniversity Center for Biosurfaces, State University of New York at Buffalo, Buffalo, New York 14214

Amitava Banerjea • NASA Lewis Research Center, Cleveland, Ohio 44135 and Physics Depart­ment, Kent State University, Kent, Ohio 44242

F. Brochard·Wyart • Laboratoire de Physique de la Matiere Condensee, College de France, F-75231 Paris Cedex 05, France and Structure et Reactivite aux Interfaces, Universite Pierre et Marie Curie, F-75231 Paris Cedex 05, France

Manoj K. Chaudhury • Dow Corning Corporation, Midland, Michigan 46868

P. G. de Gennes· Laboratoire de Physique de la Matiere Condensee, College de France, F-75231 Paris Cedex 05, France

F. Faupel· IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598. Present address: Institut fiir Metall-physik der Universitiit Gottingen, D-3400 Gottingen, Federal Republic of Germany

John Ferrante • NASA Lewis Research Center, Cleveland, Ohio 44135

Robert J. Good· Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 14260

W. Gutowski • Division of Building, Construction and Engineering, Commonwealth Scientific and Industrial Research Organization (CSIRO), Melbourne, Australia

Richard Haight • IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598

Dan A. Hays • Webster Research Center, Xerox Corporation, Webster, New York 14580

Paul S. Ho • IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598

Hatsuo Ishida • Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio 44106

Lieng·Huang Lee • Webster Research Center, Xerox Corporation, Webster, New York 14580

Anne E. Meyer • Industry/University Center for Biosurfaces, State University of New York at Buffalo, Buffalo, New York 14214

James D. Miller • Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio 44106. Present address: Amoco Performance Products, Inc., Bound Brook, New Jersey 08805

v

vi CONTRIBUTORS

Edwin P. Plueddemann • Dow Coming Corporation, Midland, Michigan 48640

B. D. Silverman • IBM Thomas J. Watson Center, Yorktown Heights, New York 10598

John R. Smith • Physics Department, General Motors Research Laboratories, Warren, Michigan 48090

Carel J. van Oss • Department of Chemical Engineering and Department of Microbiology, State University of New York at Buffalo, Buffalo, New York 14214

Robert C. White· IBM Thomas 1. Watson Research Center, Yorktown Heights, New York 10598. Present address: Department of Electrical Engineering, Columbia University, New York, New York 10027

Richard P. Wool • Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801

Preface

For several years, I have been responsible for organizing and teaching in the fall a short course on "Fundamentals of Adhesion: Theory, Practice, and Applications" at the State University of New York at New Paltz. Every spring I would try to assemble the most pertinent subjects and line up several capable lecturers for the course. However, there has always been one thing missing-an authoritative book that covers most aspects of adhe­sion and adhesive bonding. Such a book would be used by the participants as a main reference throughout the course and kept as a sourcebook after the course had been completed. On the other hand, this book could not pretend to be one of those "All you want to know about" volumes, simply because adhesion is an interdisciplinary and ever­growing field.

For the same reason, it would be very difficult for a single individual, especially me, to undertake the task of writing such a book. Thus, I relied on the principle that one leaves the truly monumental jobs to experts, and I finally succeeded in asking several leading scientists in the field of adhesion to write separate chapters for this collection. Some chapters emphasize theoretical concepts and others experimental techniques. In the hum­ble beginning, we planned to include only twelve chapters. However, we soon realized that such a plan would leave too much ground uncovered, and we resolved to increase the coverage. After the book had evolved into thirty chapters, we started to feel that perhaps our mission had been accomplished. Originally we had thought to publish the entire project under the title Fundamentals of Adhesion; then it was deemed necessary to split a portion of it off into the second volume, Adhesive Bonding. Since these two volumes include chapters by many authors, some overlap is inevitable.

In this first volume we focus on adhesion with or without the use of an adhesive, while in the second we shall concentrate on bonding with the aid of adhesives. In this volume our major concern is the mechanisms of bond formation, while in the second volume our scope will be broadened to both bond-forming and bond-breaking processes. With both of these volumes, we hope that our readers will become familiar with both the science and technology of adhesion.

In this volume, we shall stress the fundamentals of adhesion. Chapter I is an over­view of the chemistry and physics of adhesion. Chapter 2 summarizes the ther­modynamics of adhesion. Chapters 3 and 4 cover the theories of adhesive forces across interfaces. Chapter 5 discusses briefly the dynamics of wetting. Chapters 6 and 7 investi­gate the diffusion mechanism of adhesion chiefly on the basis of the reptation theory. Chapter 8 deals with the controversial topic of electronic adhesion. Chapters 9 and 10 touch upon the phenomena of chemical interactions at the interface. Chapters 11 and 12 explore the theories of metal adhesion. Chapters 13 and 14 pave the way for us to

vii

viii PREFACE

understand thin-film adhesion related to electronic devices. Finally, Chapter 15 introduces us to the related growing field of bioadhesion, which none of us should ignore.

For better readability, all of the chapters have been refereed and separate nomen­clature lists are included at the end of most of the chapters. I should like to take this opportunity to thank the many referees for their efforts, and especially Professor Robert Good for his patience in refereeing more than one chapter for this volume. I also wish to thank all of the authors for their fine cooperation. Finally, I sincerely appreciate the support of the Webster Research Center of Xerox Corporation in helping me complete this task, and the help of Mr. F. G. Belli and Ms. E. Jonas of the Technical Information Center in preparing the indexes.

Lieng-Huang Lee August, 1990

Contents

1. The Chemistry and Physics of Solid Adhesion Lieng-Huang Lee

1. Introduction............................................. 1 2. The Four Forces of Nature ................................. 2

2.1. Carriers of Four Forces .............................. 3 2.2. Gluons and Adhesion of Nuclei ....................... 4 2.3. Nuclear Equation of State ........................... 5

3. Chemical Bonding and Intermolecular Forces .................. 6 3.1. Chemical Forces and Covalent Bonding ................ 6 3.2. Coulomb Force and Ionic Bond. . . . . . . . . . . . . . . . . . . . . . . 6 3.3. Electronegativity and Partial Ionic Bond. . . . . . . . . . . . . . . . 7 3.4. Lifshitz-van der Waals Forces Between Microscopic

Bodies. ............ . ....... . ...... . . ...... . . . . ... 8 3.5. Nonretarded Lifshitz-van der Waals Forces Between

Macroscropic Bodies ............................... 11 4. Molecular Interactions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.1. Morse Interaction Curve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.2. Perturbation Theory ................................ 17 4.3. Kitaura-Morokuma's Decomposition of Interaction

Energies .......................................... 18 4.4. Natural Bond Orbital (NBO) Donor-Acceptor

Approach ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.5. Acid-Base Interaction .............................. 21

5. Role of Diffusion in Adhesion .............................. 23 5.1. Fick's Laws of Diffusion ............................ 23 5.2. Activation Energy of Diffusion ....................... 24 5.3. Diffusion and Adhesion of Polymers. . . . . . . . . . . . . . . . . . . 24 5.4. Diffusion of Solid into Polymers ...................... 26

6. Physicochemical Bonding on Solid Surfaces ................... 26 6.1. Density of States (DOS) ............................. 26 6.2. Electron Work Function ............................. 27 6.3. Fermi Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 6.4. Frontier Orbital Concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

7. Interactions on Solid Surfaces .............................. 32 7.1. Interactions Between Two Discrete Molecules ........... 32

ix

x CONTENTS

7.2. Interactions Between a Molecule and a Solid. . . . . . . . . . . . 32 7.3. Chemisorption..................................... 33

8. Hard-Soft Acid-Base (HSAB) Principle. . . . . . . . . . . . . . . . . . . . . . 33 8.1. The HSAB Principle in Solution ...................... 33 8.2. Extension of the HSAB Principle to the Solid State ...... 34

9. Metal-to-Metal Contact .................................... 35 9.1. Metal-Metal Adhesion .............................. 36 9.2. Metal-Metal Adhesion Theory ....................... 36 9.3. Effect of Critical Separation on Metal-Metal Adhesion. . . . 36 9.4. Effect of the Acid-Base Interaction on Metal-Metal

Adhesion ......................................... 37 9.5. Effect of Crystal Structure on Metal-Metal Adhesion ..... 37 9.6. Effect of Contact Electrification on Metal-Metal

Adhesion ......................................... 38 9.7. Effect of Diffusion on Metal-Metal Adhesion ........... 38

10. Metal-Semiconductor Contact .............................. 39 10.1. Ionicity of Semiconductors. . . . . . . . . . . . . . . . . . . . . . . . . . . 40 10.2. Metal-Semiconductor Adhesion. . . . . . . . . . . . . . . . . . . . . . . 41 10.3. Effect of Chemical Reaction on Metal-Semiconductor

Interface ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 10.4. Effect of Contact Electrification on Metal-Semiconductor

Adhesion ......................................... 42 11. Metal-Salt and Metal-Oxide Adhesion ....... . . . . . . . . . . . . . . . . 45 12. Metal-Ceramic Adhesion .................................. 46 13. Metal-Superconductor Adhesion ............................ 48 14. Metal-Glass Adhesion .................................... 48 15. Metal-Diamond Adhesion ................................. 49 16. Metal-Polymer Adhesion .................................. 50

16.1. Mechanisms of Metal-Polymer Adhesion . . . . . . . . . . . . . . . 50 16.2. Classification of Polymers According to their

Wettabilities ....................................... 50 16.3. Metal Adhesion to Low Wettability Polymers. . . . . . . . . . . . 51 16.4. Metal Adhesion of Medium Wettability Polymers ........ 55 16.5. Metal Adhesion to High Wettability Polymers ........... 56 16.6. Metal-Rubber Adhesion ............................. 60 16.7. Effect of Contact Electrification on Metal-Polymer

Adhesion ......................................... 62 17. Polymer-Solid Adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

17.1. Polymer-Solid Contact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 17.2. Polymers as Adhesives .............................. 66

18. Discussion.............................................. 67 19. Summary............................................... 71 Appendix ..................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

A. Fundamental Physical Constants . . . . . . . . . . . . . . . . . . . . . . . . . 72 B. Non-SI Units Used with SI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Acknowledgment ............................................. 72

CONTENTS xi

Nomenclature 73 75 References .................................................. .

2. Thermodynamics of Adhesion w. Gutowski

1. Molecular Forces ......................................... 87 1.1. General .......................................... 87 1.2. 1Ypes of Intermolecular and Interatomic Forces, Their

Range and Magnitude ...... . . . . . . . . . . . . . . . . . . . . . . . . . 87 1.3. Classical (Microscopic) Theory of Interatomic and

Intermolecular Forces ............................... 89 1.4. Application of Quantum Field Theory for Estimation of

Interaction Force and Energy Between l\vo Solids (Macroscopic Theory) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

2. Acid-Base (Donor-Acceptor) Interactions .................... 105 2.1. Br!!lnsted and Lewis Concepts of Acid-Base

Interactions ....................................... 105 2.2. Acidity and Basicity of Solid Surfaces ................. 106 2.3. Quantitative Assessment of Acid-Base Interactions. . . . . . . 109 2.4. Acid-Base Interactions in Adhesion ................... 113

3. Thermodynamics of Surfaces ............................... 116 3.1. Surface Energy, Thermodynamic Work of Adhesion, and

Energy of Cohesion ................................ 116 3.2. Energy Equilibrium at the Interface. . . . . . . . . . . . . . . . . . . . 117 3.3. Interfacial Energy .................................. 118

4. Experimental Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 4.1. Interfacial Energy at the Liquid-Liquid and Liquid-Gas

Interface by Techniques Independent of Contact Angle .... 124 4.2. Techniques Based on Measurement of the Equilibrium

Contact Angle ..................................... 124 4.3. Techniques Based on Acid-Base Interaction Concepts .... 131

Nomenclature ................................................ 132 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

3. Theory of Adhesive Forces Across Interfaces: 1. The Lifshitz-van der Waals Component of Interaction and Adhesion Robert J. Good and Manoj K. Chaudhury

1. Introduction............................................. 137 2. Theory of van der Waals Interactions Across Interfaces .......... 137

2.1. The Pairwise-Addition Approximation ................. 137 2.2. The Lifshitz Theory: General Considerations ............ 140

xii CONTENTS

3. Interactions Between Condensed Phases ...................... 142 4. Application to Interfacial Tension and Free Energy ............. 145

Appendix. A Note on Electrostatic and Electromagnetic Units in the Theory of Adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Nomenclature ................................................ 149 References ................................................... 150

4. Theory of Adhesive Forces Across Interfaces: 2. Interfacial Hydrogen Bonds as Acid-Base Phenomena and as Factors Enhancing Adhesion

Robert J. Good, Manoj K. Chaudhury, and Carel J. van Oss

1. Introduction............................................. 153 2. Monopolar and Bipolar Substances and Hydrogen Bonds per se . . . 154 3. Classification of Binary Systems ............................ 157 4. Surface Parameters 'Y(f) and 'Y8 That Give Direct Characterization

of Acidic and Basic Behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 5. Application of the Lewis Acid-Base Parameters ............... 162

5.1. 'Y(f) and 'Y8 Values of Selected Liquids. . . . . . . . . . . . . . . . . 163 5.2. Application to Selected Solid Surfaces ................. 164 5.3. Discussion of 'Y(f) and 'Y8 Values in Table 5 ............ 165

6. An Anomaly ............................................ 167 7. Applications............................................. 167

7.1. Negative Interfacial Tensions: An Illustration ............ 167 7.2. Application to Adhesion and Adhesive Bonding. . . . . . . . . . 168 7.3. The Effective Range of Acid-Base Interactions. . . . . . . . . . 169 7.4. Other Developments and Applications. . . . . . . . . . . . . . . . . . 169

8. Summary............................................... 170 Nomenclature ................................................ 170 References ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

5. The Dynamics of Wetting

P. G. de Gennes

1. Introduction............................................. 173 2. The Final State in Complete Wetting ......................... 174 3. The Dynamics of Dry Spreading ............................ 175 4. Special Systems .......................................... 177

4.1. Polymer Melts ..................................... 177 4.2. Langmuir-Blodgett Deposition ....................... 177

5. Conclusions............................................. 178 Acknowledgments ............................................. 178 Nomenclature ................................................ 178 References ................................................... 179

CONTENTS xiii

6. Kinetics of Polymer-Polymer Interdiffusion F. Brochard-Wyart

1. Introduction............................................. 181 1.1. Interdiffusion Coefficient ............................ 181 1.2. Interdiffusion Profiles ............................... 186

2. Dynamics of Pure Melts-Autoadhesion . . . . . . . . . . . . . . . . . . . . . . 188 2.1. Polymer Melts: Statics and Dynamics .................. 189 2.2. Reptation and Self-Diffusion of Entangled Polymers ...... 190 2.3. Interdiffusion of Labeled P;'/Unlabeled P A Polymers ..... 191 2.4. Autoadhesion: Polymer-Polymer Welding .............. 193

3. Dynamics of P A/PB Mixtures: Heterojunctions ................. 196 3.1. The Flory-Huggins Free Energy of Mixing ............. 196 3.2. Microscopic Theory of Mutual Diffusion ............... 197 3.3. Interdiffusion of Small Chains (N A' NB < Ne ) ••. . . • . . . . • 199 3.4. Interdiffusion of Entangled Polymers (N A' NB > Ne ) ..... 201 3.5. P AIPB Welding (Short-Time Behavior) ................. 202

4. Conclusions............................................. 202 Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 Nomenclature ................................................ 204 References ................................................... 204

7. Welding, Tack, and Green Strength of Polymers Richard P. Wool

1. Introduction............................................. 207 2. Theory................................................. 208

2.1. Molecular Dynamics of Random-Coil Chains . . . . . . . . . . . . 208 2.2. Molecular Description of a Polymer-Polymer Interface ... 209 2.3. Concentration Profile ............................... 214 2.4. Scaling Laws for a Polymer-Polymer Interface .......... 215

3. Fractal Nature of a Diffusion Front . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 3.1. Atomic Diffusion Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 3.2. Computer. Analysis of Polymer-Polymer Interdiffusion .... 218

4. Microstructural Fracture Criteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 4.1. Chain Pullout ..................................... 220 4.2. Fracture Mechanics of Welding ....................... 222 4.3. Stages of Healing .................................. 227

5. Healing Experiments ...................................... 229 5.1. Tack and Green Strength ............................ 229

6. Welding of Polymer Interfaces .............................. 233 6.1. Wedge Cleavage Experiment ......................... 233

7. Lap Shear Welding ....................................... 241 7.1. Polystyrene Welding ................................ 241

xiv CONTENTS

8. Polymer Processing Weld Lines ............................. 242 8.1. Compression Molding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

Acknowledgments. . . . . . . . . .......... . . . . ....... . . .... .. . . . . . . . 244 Nomenclature ................................................ 244 References ................................................... 246

8. Role of Electrostatics in Adhesion Dan A. Hays

1. Introduction............................................. 249 2. Electrostatic Concepts ..................................... 251 3. Electrostatic Force Between a Point Charge and Planar Material. . . 253 4. Electrostatic Force Between Charged Planar Materials ........... 254 5. Charge Exchange Properties of Materials ..................... 258

5.1. Metal-Metal Charging .............................. 259 5.2. Metal-Insulator Charging. . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 5.3. Insulator-Insulator Charging ......................... 265

6. Charge Penetration Depth in Insulators ....................... 266 7. Charge Back-Flow During Separation ........................ 268 8. Interfacial Polarization .................................... 269 9. Charged Particle Adhesion ........................... :..... 270

10. Summary............................................... 275 Nomenclature ................................................ 275 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

9. Adhesion Through Silane Coupling Agents Edwin P. Plueddemann

1. Introduction............................................. 279 2. General Equilibrium Conditions ............................. 280

2.1. Reaction with the Mineral ........................... 281 2.2. Hydrophobic Interphase Region. . . . . . . . . . . . . . . . . . . . . . . 281 2.3. Optimum Structure in the Interphase Region ............ 282

3. Cross linking the Interphase Region .......................... 285 3.1. Inhibition of Cure by Fillers . . . . . . . . . . . . . . . . . . . . . . . . . . 285 3.2. Inhibition of Cure by Silanes ......................... 286 3.3. Additional Crosslinking Through the Coupling Agent ..... 286 3.4. Additional Crosslinking Through Siliconates ............ 287

4. Conclusion.............................................. 289 References ................................................... 289

10. Adhesive-Adherend Interface and Interphase James D. Miller and Hatsuo Ishida

1. Introduction............................................. 291 2. Interface................................................ 292

CONTENTS xv

3. Chemical Modifiers ....................................... 297 4. Evidence of Chemical Bonding ............................. 302 5. Interphase............................................... 308

5.1. Theories.......................................... 308 5.2. Properties......................................... 310 5.3. Silane Interphase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 5.4. Other Additives .................................... 318

6. FutureDirections......................................... 319 References ................................................... 320

11. Adhesion at Metal Interfaces Amitava Banerjea, John Ferrante, and John R. Smith

1. Introduction............................................. 325 2. Theoretical Considerations ................................. 327

2.1. First-Principle Calculations .......................... 328 2.2. Jellium-Model Calculations .......................... 329

3. Binding Energies ......................................... 333 3.1. Fully Three-Dimensional Calculations. . . . . . . . . . . . . . . . . . 335 3.2. Universality in the Shapes of the Binding Energy

Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337 4. Semiempirical Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

4.1. Embedded-Atom Method ............................ 338 4.2. Equivalent-Crystal Theory ........................... 339

5. Concluding Remarks ...................................... 345 Nomenclature ................................................ 346 References ................................................... 347

12. Hard-Soft Acid-Base (HSAB) Principle for Solid Adhesion and Surface Interactions Lieng-Huang Lee

1. Introduction............................................. 349 2. HSAB Principle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

2.1. HSAB Principle for Inorganic Reactions. . . . . . . . . . . . . . . . 349 2.2. HSAB Principle for Organic Reactions and the Frontier

Orbital Approach .................................. 350 2.3. Perturbation Equation ............................... 350 2.4. Electronegativity and Absolute Hardness ............... 351

3. Extension of the HSAB Principle to Solid Interactions .......... 353 3.1. Electronic Band Structures of Solids ................... 353 3.2. Average Energy Gap and Absolute Hardness ............ 354 3.3. Energy Gaps and Absolute Hardness Values for

Semiconductors .................................... 354 3.4. Absolute Hardness of Solid .......................... 357

xvi CONTENTS

4. Applications of the HSAB Principle to Adhesion and Surface Interactions Between Metals and Polymers .................... 358

5. Conclusions............................................. 359 Acknowledgments ............................................. 359 Nomenclature ................................................ 360 References .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

13. Interface Design for Thin Film Adhesion John E. E. Baglin

1. Introduction............................................. 363 2. Origins of Thin Film Adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364

2. 1. Interface Energy ................................... 364 2.2. Interface Fracture .................................. 365

3. Adhesion Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 3.1. Dependence on Application .......................... 366 3.2. Adhesion Measurements ............................. 367

4. Adhesion Enhancement .................................... 370 4.1. Processing Strategies ............................... 370 4.2. Ion Beam Techniques ............................... 371

5. Summary............................................... 381 References ................................................... 381

14. Chemistry, Microstructure, and Adhesion of Metal-Polymer Interfaces Paul S. Ho, Richard Haight, Robert C. White, B. D. Silverman, and F. Faupel

1. Introduction............................................. 383 2. Chemical Bonding and Electronic Structure ................... 385

2.1. Electronic Structure of Polyimide Surface . . . . . . . . . . . . . . . 385 2.2. Chromium-Polyimide Interface ....................... 388 2.3. Copper-Polyimide Interface. . . . . . . . . . . . . . . . . . . . . . . . . . 391

3. Interfacial Microstructure .................................. 393 4. Adhesion and Deformation ................................. 399 5. Summary............................................... 404

Acknowledgments ............................................. 405 References ................................................... 405

15. Aspects of Bioadhesion Robert E. Baier and Anne E. Meyer

1. Introduction............................................. 407 2. Analytical Methods Most Applicable to Bioadhesion Studies ..... 409

CONTENTS xvii

3. Experimental Requirements ................................ 410 4. Bioadhesion of Microbes .................................. 410 5. Bioadhesion of Macrobiota .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 6. Bioadhesion from Blood. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 7. Bioadhesion in Hard and Soft Tissues. . . . . . . . . . . . . . . . . . . . . . . . 417 8. Research Priorities for Future Bioadhesion Studies. . . . . . . . . . . . . . 419 9. Summary and Conclusions ................................. 420

10. Postscript: Universality of the Principle of Bioabhesion . . . . . . . . . . 421 Acknowledgments .................................... ,........ 422 References ................................................... 422

About the Contributors ...................................... 427

Author Index 431

Subject Index 437