The Colloidal Domain

Preface to the First Edition xv
Preface to the Second Edition xvii
Preface to the Third Edition xix
Physical Constants xxi
Symbols xxiii
About the Author xxvii
Introduction/Why Colloidal Systems Are Important xxix
The Colloidal Domain Encompasses Many Biological and Technological Systems xxix
Understanding of Colloidal Phenomena Is Advancing Rapidly xxxi
Association Colloids Display Key Concepts That Guided the Structure of This Book xxxii

1 Solutes and Solvents, Self-assembly of Amphiphiles 1
1.1 Understanding the Origin of Entropy and Enthalpy of Mixing Provides Useful Molecular Insight into Many Colloidal Phenomena 3
1.2 The Chemical Potential Is a Central Thermodynamic Concept in the Description of Multicomponent Systems 10
1.3 Amphiphilic Self-assembly Processes Are Spontaneous, Are Characterized by Start-Stop Features, and Produce Aggregates with Well-defined Properties 17
1.4 Amphiphilic Molecules Are Liquid-like in Self-assembled Aggregates 22
1.5 Surfactant Numbers Provide Useful Guides for Predicting Aggregate Structures 25
1.6 Solvophobicity Drives Amphiphilic Aggregation 28
1.7 Brownian Motion Gives Rise to Molecular Diffusion 31

2 Surface Chemistry and Monolayers 41
2.1 We Can Comprehend Surface Tension in Terms of Surface Free Energy 44
2.2 Several Techniques Measure Surface Tension 52
2.3 Capillary Condensation, Ostwald Ripening, Nucleation, and Particle Adsorption on Interfaces Are Practical Manifestations of Surface Phenomena 54
2.4 Thermodynamics Can Be Extended to Include Surface Contributions 62
2.5 Monolayers of Insoluble Amphiphiles Form Independent Two-dimensional Systems 68
2.6 A Range of Experimental Methods Can Be Used to Study Surfaces and Interfaces 70
2.7 Evaporation at a Surface Leads to Intriguing Nonequilibrium Phenomena 75

3 Electrostatic Interactions in Colloidal Systems 85
3.1 Intermolecular Interactions Can Be Expressed as the Sum of Five Terms 88
3.2 Multipole Expansion of the Charge Distribution Provides a Convenient Way to Express Electrostatic Interactions Between Molecules 89
3.3 When Electrostatic Interactions Are Smaller than the Thermal Energy, We Can Use Angle-averaged Potentials to Evaluate Them and Obtain the Free Energy 95
3.4 Induced Dipoles Contribute to Electrostatic Interactions 98
3.5 Separating Ion-Ion Interactions from Contributions of Dipoles and Higher Multipoles in the Poisson Equation Simplifies Dealing with Condensed Phases 100
3.6 The Poisson Equation Containing Solvent-averaged Properties Describes the Free Energy of Ion Solvation 106
3.7 Self-assembly, Ion Adsorption, and Surface Titration Play an Important Role in Determining Properties of Charged Interfaces 107
3.8 The Poisson-Boltzmann Equation Can Be Used to Calculate the Ion Distribution in Solution 110
3.9 The Electrostatic Free Energy Is Composed of One Contribution from the Direct Charge-Charge Interaction and One Due to the Entropy of the Nonuniform Distribution of Ions in Solution 120

4 Structure and Properties of Micelles 129
4.1 Micelle Formation Is a Cooperative Association Process 132
4.2 We Can Measure Critical Micelle Concentrations, Aggregation Number, Micelle Structure, and Characteristic Lifetimes by a Number of Methods 142
4.3 Scattering Provides Very Useful Techniques for Studying Micellar Structure and Colloid Systems in General 150
4.4 Micelles Is Formed by Surfactants with a Variety of Head Groups and Can Adopt Several Shapes 160
4.5 Micelles Are Used to Solubilize Apolar Substances 167

5 Forces in Colloidal Systems 175
5.1 Electrostatic Double-layer Forces Are Long-ranged 180
5.2 van der Waals Forces Are Dominated by Quantum Mechanical Dispersion Forces 193
5.3 Electrostatic Interactions Generate Attractions by Correlations 205
5.4 Measuring Surface Forces 211
5.5 Density Variations Can Generate Attractive and Oscillatory Forces 217
5.6 Entropy Effects Influence the Forces Between Liquid-like Surfaces 226
5.7 The Strength of the Hydrophobic Interaction Shows an Unexpected Temperature Dependence 229
5.8 Hydrodynamic Interactions Influence the Dynamic Properties of Colloidal Systems 235

6 Bilayer Systems 241
6.1 Bilayers Show a Rich Variation with Respect to Local Chemical Structure and Global Folding 244
6.2 Bilayers Can Adopt Many Different Global Structures 254
6.3 Transport Across Bilayers Can Be Accomplished in Several Different Ways 262
6.4 The Lipid Bilayer Supports a Range of Central Metabolic Processes in the Living Cell 270

7 Polymers in Colloidal Systems 281
7.1 Single Polymer Chains Feature a Variety of Conformations in Solution 285
7.2 Thermodynamic and Transport Properties of Polymer Solutions Change Dramatically When Coils Overlap at Higher Concentrations 296
7.3 Polymers May Associate to Form a Variety of Structures 304
7.4 Polymers at Surfaces Play an Important Role in Colloidal Systems 309

8 Colloidal Stability 319
8.1 Colloidal Stability Involves Both Thermodynamic and Kinetic Factors 322
8.2 The DLVO Theory Provides a Basic Framework for Thinking About Kinetic Colloidal Stability 325
8.3 Kinetics of Aggregation Allow Us to Predict How Fast Colloidal Systems Will Coagulate 333
8.4 Electrokinetic Phenomena Are Used to Determine Zeta Potentials of Charged Surfaces and Particles 344

9 Colloidal Sols 355
9.1 Colloidal Sols Can Be Formed by Dispersion, Precipitation, or Chemical Synthesis 358
9.2 Colloidal Particles Acquire Surface Charges by Specific Ion Adsorption 362
9.3 Clays Are Colloidal Sols Whose Surface Charge Density Reflects the Chemistry of Their Crystal Structure 366
9.4 Polymer and Lipid-based Particles Can Be Made To Serve a Number of Purposes 369
9.5 Aerosols Involve Particles in the Gas Phase 373

10 Phase Equilibria, Phases, and Their Applications 383
10.1 Phase Diagrams Depicting Colloidal Systems Are Generally Richer Than Those for Molecular Systems 386
10.2 Examples Illustrate the Importance of Phase Equilibria for Colloidal Systems 397
10.3 We Obtain an Understanding of the Factors That Determine Phase Equilibria by Calculating Phase Diagrams 405
10.4 Continuous Phase Transitions Can Be Described by Critical Exponents 420

11 Microemulsions, Emulsions, and Foams 427
11.1 Amphiphiles Form a Semiflexible Elastic Film at Interfaces 430
11.2 Microemulsions Are Thermodynamically Stable Isotropic Solutions That Display a Range of Self-assembly Structures 433
11.3 Macroemulsions Consist of Drops of One Liquid in Another 444
11.4 Foams Consist of Gas Bubbles Dispersed in a Liquid or Solid Medium 459

12 Epilogue 469
12.1 Colloid Science Has Changed from a Reductionistic to a Holistic Perspective During the Twentieth Century 469
12.2 Quantum Mechanics, Statistical Mechanics, and Thermodynamics Provide the Conceptual Basis for Describing the Equilibrium Properties of the Colloidal Domain 471
12.3 Intramolecular, Intermolecular, and Surface Forces Determine the Equilibrium Properties and Structure of Colloidal Systems 473
12.4 Crucial Interplay Between the Organizing Energy and the Randomizing Entropy Governs the Colloidal World 474
12.5 The Dynamic Properties of a Colloidal System Arise from a Combination of the Thermal Brownian Motion of the Individual Particles and the Collective Motion of the Media 476

Index 479