Table of Contents

Preface xix

1 Introduction 1

1.1 General Classification of Surface Active Agents 2

1.2 Anionic Surfactants 2

1.2.1 Carboxylates 3

1.2.2 Sulphates 4

1.2.3 Sulphonates 4

1.2.4 Phosphate-containing Anionic Surfactants 5

1.3 Cationic Surfactants 6

1.4 Amphoteric (Zwitterionic) Surfactants 7

1.5 Nonionic Surfactants 8

1.6 Speciality Surfactants – Fluorocarbon and Silicone Surfactants 13

1.7 Polymeric Surfactants 14

1.8 Toxicological and Environmental Aspects of Surfactants 15

References 16

2 Physical Chemistry of Surfactant Solutions 19

2.1 Properties of Solutions of Surface Active Agents 19

2.2 Solubility–Temperature Relationship for Surfactants 25

2.3 Thermodynamics of Micellization 26

2.4 Micellization in Surfactant Mixtures (Mixed Micelles) 34

2.5 Surfactant–Polymer Interaction 39

References 50

3 Phase Behavior of Surfactant Systems 53

3.1 Solubility–Temperature Relationship for Ionic Surfactants 57

3.2 Surfactant Self-Assembly 58

3.3 Structure of Liquid Crystalline Phases 59

3.4 Experimental Studies of the Phase Behaviour of Surfactants 62

3.5 Phase Diagrams of Ionic Surfactants 65

3.6 Phase Diagrams of Nonionic Surfactants 66

References 71

4 Adsorption of Surfactants at the Air/Liquid and Liquid/Liquid Interfaces 73

4.1 Introduction 73

4.2 Adsorption of Surfactants 74

4.3 Interfacial Tension Measurements 80

References 84

5 Adsorption of Surfactants and Polymeric Surfactants at the Solid/Liquid Interface 85

5.1 Introduction 85

5.2 Surfactant Adsorption 86

5.3 Adsorption of Polymeric Surfactants at the Solid/Liquid Interface 93

5.4 Adsorption and Conformation of Polymeric Surfactants at Interfaces 96

5.5 Experimental Methods for Measurement of Adsorption Parameters for Polymeric Surfactants 102

References 112

6 Applications of Surfactants in Emulsion Formation and Stabilisation 115

6.1 Introduction 115

6.2 Physical Chemistry of Emulsion Systems 117

6.3 Mechanism of Emulsification 123

6.4 Methods of Emulsification 126

6.5 Role of Surfactants in Emulsion Formation 127

6.6 Selection of Emulsifiers 134

6.7 Cohesive Energy Ratio (CER) Concept for Emulsifier Selection 140

6.8 Critical Packing Parameter (CPP) for Emulsifier Selection 142

6.9 Creaming or Sedimentation of Emulsions 143

6.10 Flocculation of Emulsions 150

6.11 Ostwald Ripening 154

6.12 Emulsion Coalescence 155

6.13 Phase Inversion 158

6.14 Rheology of Emulsions 159

6.15 Interfacial Rheology 162

6.16 Investigations of Bulk Rheology of Emulsion Systems 171

6.17 Experimental Methods for Assessing Emulsion Stability 182

References 184

7 Surfactants as Dispersants and Stabilisation of Suspensions 187

7.1 Introduction 187

7.2 Role of Surfactants in Preparation of Solid/Liquid Dispersions 188

7.3 Effect of Surfactant Adsorption 199

7.4 Wetting of Powders by Liquids 201

7.5 Rate of Penetration of Liquids 203

7.6 Structure of the Solid/Liquid Interface 204

7.7 Structure of the Electrical Double Layer 206

7.8 Electrical Double Layer Repulsion 207

7.9 Van der Waals Attraction 208

7.10 Total Energy of Interaction: Deryaguin–Landau–Verwey–Overbeek (DLVO) Theory 210

7.11 Criteria for Stabilisation of Dispersions with Double Layer Interaction 211

7.12 Electrokinetic Phenomena and the Zeta Potential 212

7.13 Calculation of Zeta Potential 214

7.14 Measurement of Electrophoretic Mobility 216

7.15 General Classification of Dispersing Agents 217

7.16 Steric Stabilisation of Suspensions 218

7.17 Interaction Between Particles Containing Adsorbed Polymer Layers 219

7.18 Criteria for Effective Steric Stabilisation 224

7.19 Flocculation of Sterically Stabilised Dispersions 224

7.20 Properties of Concentrated Suspensions 225

7.21 Characterisation of Suspensions and Assessment of their Stability 231

7.22 Bulk Properties of Suspensions 235

7.23 Sedimentation of Suspensions and Prevention of Formation of Dilatant Sediments (Clays) 249

7.24 Prevention of Sedimentation and Formation of Dilatant Sediments 253

References 256

8 Surfactants in Foams 259

8.1 Introduction 259

8.2 Foam Preparation 260

8.3 Foam Structure 261

8.4 Classification of Foam Stability 262

8.5 Drainage and Thinning of Foam Films 263

8.6 Theories of Foam Stability 267

8.7 Foam Inhibitors 274

8.8 Physical Properties of Foams 278

8.9 Experimental Techniques for Studying Foams 281

References 283

9 Surfactants in Nano-Emulsions 285

9.1 Introduction 285

9.2 Mechanism of Emulsification 287

9.3 Methods of Emulsification and the Role of Surfactants 289

9.4 Preparation of Nano-Emulsions 290

9.5 Steric Stabilization and the Role of the Adsorbed Layer Thickness 294

9.6 Ostwald Ripening 296

9.7 Practical Examples of Nano-Emulsions 298

References 307

10 Microemulsions 309

10.1 Introduction 309

10.2 Thermodynamic Definition of Microemulsions 310

10.3 Mixed Film and Solubilisation Theories of Microemulsions 312

10.4 Thermodynamic Theory of Microemulsion Formation 316

10.5 Free Energy of Formation of Microemulsion 318

10.6 Factors Determining W/O versus O/W Microemulsions 320

10.7 Characterisation of Microemulsions Using Scattering Techniques 321

References 333

11 Role of Surfactants in Wetting, Spreading and Adhesion 335

11.1 General Introduction 335

11.2 Concept of Contact Angle 338

11.3 Adhesion Tension 340

11.4 Work of Adhesion W a 342

11.5 Work of Cohesion 342

11.6 Calculation of Surface Tension and Contact Angle 343

11.7 Spreading of Liquids on Surfaces 346

11.8 Contact Angle Hysteresis 346

11.9 Critical Surface Tension of Wetting and the Role of Surfactants 349

11.10 Effect of Surfactant Adsorption 351

11.11 Measurement of Contact Angles 352

11.12 Dynamic Processes of Adsorption and Wetting 356

11.13 Wetting Kinetics 364

11.14 Adhesion 368

11.15 Deposition of Particles on Surfaces 379

11.16 Particle–Surface Adhesion 389

11.17 Role of Particle Deposition and Adhesion in Detergency 393

References 396

12 Surfactants in Personal Care and Cosmetics 399

12.1 Introduction 399

12.2 Surfactants Used in Cosmetic Formulations 402

12.3 Cosmetic Emulsions 403

12.4 Nano-Emulsions in Cosmetics 412

12.5 Microemulsions in Cosmetics 413

12.6 Liposomes (Vesicles) 413

12.7 Multiple Emulsions 416

12.8 Polymeric Surfactants and Polymers in Personal Care and Cosmetic Formulations 418

12.9 Industrial Examples of Personal Care Formulations and the Role of Surfactants 419

References 432

13 Surfactants in Pharmaceutical Formulations 433

13.1 General Introduction 433

13.2 Surfactants in Disperse Systems 437

13.3 Electrostatic Stabilisation of Disperse Systems 444

13.4 Steric Stabilization of Disperse Systems 447

13.5 Surface Activity and Colloidal Properties of Drugs 452

13.6 Biological Implications of the Presence of Surfactants in Pharmaceutical Formulations 460

13.7 Aspects of Surfactant Toxicity 462

13.8 Solubilised Systems 464

13.9 Pharmaceutical Suspensions 471

13.10 Pharmaceutical Emulsions 477

13.11 Multiple Emulsions in Pharmacy 482

13.12 Liposomes and Vesicles in Pharmacy 487

13.13 Nano-particles, Drug Delivery and Drug Targeting 491

13.14 Topical Formulations and Semi-solid Systems 494

References 499

14 Applications of Surfactants in Agrochemicals 503

14.1 Introduction 503

14.2 Emulsifiable Concentrates 506

14.3 Concentrated Emulsions in Agrochemicals (EWs) 524

14.4 Suspension Concentrates (SCs) 537

14.5 Microemulsions in Agrochemicals 558

14.6 Role of Surfactants in Biological Enhancement 567

References 592

15 Surfactants in the Food Industry 595

15.1 Introduction 595

15.2 Interaction Between Food-grade Surfactants and Water 596

15.3 Proteins as Emulsifiers 601

15.4 Protein–Polysaccharide Interactions in Food Colloids 604

15.5 Polysaccharide–Surfactant Interactions 606

15.6 Surfactant Association Structures, Microemulsions and Emulsions in Food 608

15.7 Effect of Food Surfactants on the Rheology of Food Emulsions 609

15.8 Practical Applications of Food Colloids 626

References 629

Subject Index 631

About the Author

After finishing his PhD at Alexandria University, Tharwat Tadros was appointed lecturer in Physical Chemistry (1962-1966) at the same University. Between 1966 and 1969, he spent a sabbatical at the Agricultural University of Wageningen and T.N.O in Delft, the Netherlands. Thereafter he joined I.C.I. and ZENECA until 1994, where he researched various fields of surfactants, emulsions, suspensions, microemulsions, wetting spreading and adhesion and rheology. During that period he was also appointed visiting professor at Imperial College London, Bristol University and Reading University. In 1992, he was elected President of the International Association of Colloid and Interface Science. Since leaving ZENECA, Dr Tadros has worked as a consultant for various industries and also given several courses in his specialized field. He is the recipient of two medals from the Royal Society of Chemistry in the UK, and has more than 250 scientific papers to his name.

Reviews

"This book provides a rich...source of information, especially for the industrial chemist who wishes to learn more about this fascinating world. ...this work will be consulted frequently by the practicing industrial surfactant chemist."
Angewandte Chemie

"This handbook meets the need for a comprehensive survey of surfactants and their properties, with a strong emphasis on applications and their correlation to the fundamentals. The author covers their classification, physical properties, phase behavior, adsorption, but also effects, such as wetting, spreading and adhesion, as well as industrial applications in personal care and cosmetics, pharmaceuticals, agrochemicals and food products. The author is a well-known expert on the topic of surfactants, with much experience in colloid science. In this volume, he uses his industrial experience to close the gap between the already published fundamentals of surfactants and their application in practice. Therefore, this book is recommended as a useful guideline for all scientists working in academics or industry with surface-active substances, especially in research and development. Together with 'Emulsions, Foams and Suspensions written by Laurier L. Schramm' and also published by Wiley-VCH this year, it is a basical platform for very special investigations in the interesting field of surfactants, such as sustainable enrichment of valuable plant ingredients by foaming for their further use as drugs or food additives."
AFS: Advances in Food Sciences

Aus Gutachten zum Projektvorschlag:

"Dr. Tadros ist ein sehr angesehener Wissenschaftler im Bereich der Oberflächenchemie, bekannt für seinen guten Schreibstil." Prof. Krister Holmberg, Chalmers Univ., Göteborg, Sweden
"Der Autor ist ein bekannter Experte für oberflächenaktive Substanzen." Univ. Essen, Germany
"Professor Tadros ist auf dem Gebiet der Tenside ein bekannter und anerkannter Experte. Durch seine Industrieerfahrung kann es gelingen, die Lücke zwischen Grundlagen von Tensiden und Relevanz bzw. Anwendung derselben in der Praxis zu schließen."
Dr. Oetter, BASF AG, LU
"Dr. Tadros ist in der Welt der Kolloidchemie wohl bekannt. Es ist zu erwarten, dass ein qualitativ ansprechendes Buch entsteht." Univ. Bayreuth
"Dr. Tadros ist ein bekannter Wissenschaftler auf dem Gebiet der Emulsionschemie und der Rheologie, der in der Lage ist, sowohl über Grundlagen als auch über die Anwendungen von Tensiden zu schreiben." Yokohama National Univ., Japan
"Der Autor ist ein bekannter Wissenschaftler mit langjähriger Erfahrung in Kolloidchemie." Henkel KGaA, Düsseldorf


"Alles in allem ist mein Eindruck, dass Industriechemiker, die sich mit grenzflächenaktiven Stoffen beschäftigen, oft auf dieses Werk zurückgreifen werden."
Angewandte Chemie

"Diese Vielfalt interessanter praktischer Informationen zeigt insbesondere das universelle Auftreten von Tensiden in sehr unterschiedlichen Bereichen des Alltagslebens auf und macht dieses Buch zu einer interessanten Ergänzung zu der sonst verfügbaren Literatur über Amphiphile."
Chemie Ingenieur Technik