Surfactants and Interfacial Phenomena

Milton J. Rosen, PhD, is Professor Emeritus of Chemistry at Brooklyn College of the City University of New York. He is also the Director (ret.) of the university's Surfactant Research Institute, a pioneering organization that he founded in 1987.Joy T. Kunjappu, PhD, DSc, is a chemistry educator, consultant, and former Adjunct Professor at Columbia University and Brooklyn College. His areas of research interest include surfactant and surface science, organic chemistry, and photochemistry.

• Preface xv1 Characteristic Features of Surfactants 1I. Conditions under which Interfacial Phenomena and Surfactants Become Significant 2II. General Structural Features and Behavior of Surfactants 2A. General Use of Charge Types 4B. General Effects of the Nature of the Hydrophobic Group 51. Length of the Hydrophobic Group 52. Branching, Unsaturation 53. Aromatic Nucleus 54. Polyoxypropylene or Polyoxyethylene (POE) Units 55. Perfluoroalkyl or Polysiloxane Group 6III. Environmental Effects of Surfactants 6A. Surfactant Biodegradability 6B. Surfactant Toxicity; Skin Irritation 7IV. Characteristic Features and Uses of Commercially Available Surfactants 8A. Anionics 91. Carboxylic Acid Salts 92. Sulfonic Acid Salts 113. Sulfuric Acid Ester Salts 154. Phosphoric and Polyphosphoric Acid Esters 175. Fluorinated Anionics 18B. Cationics 191. Long-Chain Amines and Their Salts 202. Acylated Diamines and Polyamines and Their Salts 203. Quaternary Ammonium Salts 204. Polyoxyethylenated Long-Chain Amines 225. Quaternized POE Long-Chain Amines 226. Amine Oxides 22C. Nonionics 231. Polyoxyethylenated Alkylphenols, Alkylphenol "Ethoxylates" 232. Polyoxyethylenated Straight-Chain Alcohols 243. Polyoxyethylenated Polyoxypropylene Glycols 254. Polyoxyethylenated Mercaptans 255. Long-Chain Carboxylic Acid Esters 266. Alkanolamine "Condensates," Alkanolamides 277. Tertiary Acetylenic Glycols and Their "Ethoxylates" 288. Polyoxyethylenated Silicones 289. N-Alkylpyrrolid(in)ones 2910. Alkylpolyglycosides 29D. Zwitterionics 301. pH-Sensitive Zwitterionics 302. pH-Insensitive Zwitterionics 32E. Newer Surfactants Based Upon Renewable Raw Materials 321. α-Sulfofatty Acid Methyl Esters (SME) 322. Acylated Aminoacids 333. Nopol Alkoxylates 34V. Some Useful Generalizations 34VI. Electronic Searching of the Surfactant Literature 35References 36Problems 372 Adsorption of Surface-Active Agents at Interfaces: The Electrical Double Layer 39I. The Electrical Double Layer 40II. Adsorption at the Solid–Liquid Interface 44A. Mechanisms of Adsorption and Aggregation 44B. Adsorption Isotherms 481. The Langmuir Adsorption Isotherm 50C. Adsorption from Aqueous Solution onto Adsorbents with Strongly Charged Sites 531. Ionic Surfactants 532. Nonionic Surfactants 593. pH Change 594. Ionic Strength 605. Temperature 60D. Adsorption from Aqueous Solution onto Nonpolar, Hydrophobic Adsorbents 60E. Adsorption from Aqueous Solution onto Polar Adsorbents without Strongly Charged Sites 63F. Effects of Adsorption from Aqueous Solution on the Surface Properties of the Solid Adsorbent 631. Substrates with Strongly Charged Sites 632. Nonpolar Adsorbents 65G. Adsorption from Nonaqueous Solution 65H. Determination of the Specific Surface Areas of Solids 66III. Adsorption at the Liquid–Gas (L/G) and Liquid–Liquid (L/L) Interfaces 66A. The Gibbs Adsorption Equation 67B. Calculation of Surface Concentrations and Area Per Molecule at the Interface by Use of the Gibbs Equation 69C. Effectiveness of Adsorption at the L/G and L/L Interfaces 71D. The Szyszkowski, Langmuir, and Frumkin Equations 99E. Efficiency of Adsorption at the L/G and L/L Interfaces 100F. Calculation of Thermodynamic Parameters of Adsorption at the L/G and L/L Interfaces 104G. Adsorption from Mixtures of Two Surfactants 113References 115Problems 1213 Micelle Formation by Surfactants 123I. The Critical Micelle Concentration (CMC) 123II. Micellar Structure and Shape 126A. The Packing Parameter 126B. Surfactant Structure and Micellar Shape 127C. Liquid Crystals 128D. Rheology of Surfactant Solutions 131III. Micellar Aggregation Numbers 132IV. Factors Affecting the Value of the CMC in Aqueous Media 140A. Structure of the Surfactant 1401. The Hydrophobic Group 1402. The Hydrophilic Group 1583. The Counterion in Ionic Surfactants; Degree of Binding to the Micelle 1604. Empirical Equations 164B. Electrolyte 166C. Organic Additives 1671. Class I Materials 1672. Class II Materials 168D. The Presence of a Second Liquid Phase 169E. Temperature 170V. Micellization in Aqueous Solution and Adsorption at the Aqueous Solution–Air or Aqueous Solution–Hydrocarbon Interface 170A. The CMC/C20 Ratio 171VI. CMCs in Nonaqueous Media 179VII. Equations for the CMC Based on Theoretical Considerations 180VIII. Thermodynamic Parameters of Micellization 184IX. Mixed Micelle Formation in Mixtures of Two Surfactants 191References 192Problems 2004 Solubilization by Solutions of Surfactants: Micellar Catalysis 202I. Solubilization in Aqueous Media 203A. Locus of Solubilization 203B. Factors Determining the Extent of Solubilization 2061. Structure of the Surfactant 2072. Structure of the Solubilizate 2093. Effect of Electrolyte 2094. Effect of Monomeric Organic Additives 2105. Effect of Polymeric Organic Additives 2116. Mixed Anionic–Nonionic Micelles 2127. Effect of Temperature 2128. Hydrotropy 214C. Rate of Solubilization 214II. Solubilization in Nonaqueous Solvents 215A. Secondary Solubilization 218III. Some Effects of Solubilization 218A. Effect of Solubilization on Micellar Structure 218B. Change in the CPs of Aqueous Solutions of Nonionic Surfactants 219C. Reduction of the CMC 223D. Miscellaneous Effects of Solubilization 223IV. Micellar Catalysis 224References 229Problems 2335 Reduction of Surface and Interfacial Tension by Surfactants 235I. Efficiency in Surface Tension Reduction 239II. Effectiveness in Surface Tension Reduction 241A. The Krafft Point 241B. Interfacial Parameter and Chemical Structural Effects 242III. Liquid–Liquid Interfacial Tension Reduction 256A. Ultralow Interfacial Tension 257IV. Dynamic Surface Tension Reduction 262A. Dynamic Regions 262B. Apparent Diffusion Coefficients of Surfactants 265References 266Problems 2706 Wetting and Its Modification by Surfactants 272I. Wetting Equilibria 272A. Spreading Wetting 2731. The Contact Angle 2752. Measurement of the Contact Angle 277B. Adhesional Wetting 278C. Immersional Wetting 281D. Adsorption and Wetting 282II. Modification of Wetting by Surfactants 285A. General Considerations 285B. Hard Surface (Equilibrium) Wetting 286C. Textile (Nonequilibrium) Wetting 288D. Effect of Additives 299III. Synergy in Wetting by Mixtures of Surfactants 300IV. Superspreading (Superwetting) 300References 303Problems 3067 Foaming and Antifoaming by Aqueous Solutions of Surfactants 308I. Theories of Film Elasticity 309II. Factors Determining Foam Persistence 313A. Drainage of Liquid in the Lamellae 313B. Diffusion of Gas through the Lamellae 314C. Surface Viscosity 315D. The Existence and Thickness of the Electrical Double Layer 315III. The Relation of Surfactant Chemical Structure to Foaming in Aqueous Solution 316A. Efficiency as a Foaming Agent 317B. Effectiveness as a Foaming Agent 317C. Low-Foaming Surfactants 325IV. Foam-Stabilizing Organic Additives 326V. Antifoaming 329VI. Foaming of Aqueous Dispersions of Finely Divided Solids 330VII. Foaming and Antifoaming in Organic Media 331References 332Problems 3348 Emulsification by Surfactants 336I. Macroemulsions 337A. Formation 338B. Factors Determining Stability 3381. Physical Nature of the Interfacial Film 3392. Existence of an Electrical or Steric Barrier to Coalescence on the Dispersed Droplets 3413. Viscosity of the Continuous Phase 3424. Size Distribution of Droplets 3425. Phase Volume Ratio 3436. Temperature 343C. Inversion 345D. Multiple Emulsions 345E. Theories of Emulsion Type 3471. Qualitative Theories 3472. Kinetic Theory of Macroemulsion Type 349II. Microemulsions 350III. Nanoemulsions 354IV. Selection of Surfactants as Emulsifying Agents 355A. The Hydrophile–Lipophile Balance (HLB) Method 356B. The PIT Method 358C. The Hydrophilic Lipophilic Deviation (HLD) Method 361V. Demulsification 361References 363Problems 3669 Dispersion and Aggregation of Solids in Liquid Media by Surfactants 368I. Interparticle Forces 368A. Soft (Electrostatic) and van der Waals Forces: Derjaguin and Landau and Verwey and Overbeek (DLVO) Theory 3691. Limitations of the DLVO Theory 374B. Steric Forces 376II. Role of the Surfactant in the Dispersion Process 378A. Wetting of the Powder 378B. Deaggregation of Fragmentation of Particle Clusters 379C. Prevention of Reaggregation 379III. Coagulation or Flocculation of Dispersed Solids by Surfactants 379A. Neutralization or Reduction of the Potential at the Stern Layer of the Dispersed Particles 380B. Bridging 381C. Reversible Flocculation 381IV. The Relation of Surfactant Chemical Structure to Dispersing Properties 382A. Aqueous Dispersions 382B. Nonaqueous Dispersions 387C. Design of New Dispersants 387References 388Problems 39010 Detergency and Its Modification by Surfactants 392I. Mechanisms of the Cleaning Process 392A. Removal of Soil from Substrate 3931. Removal of Liquid Soil 3942. Removal of Solid Soil 395B. Suspension of the Soil in the Bath and Prevention of Redeposition 3981. Solid Particulate Soil: Formation of Electrical and Steric Barriers; Soil Release Agents 3982. Liquid Oily Soil 399C. Skin Irritation (see Chapter 1, Section IIIB) 400D. Dry Cleaning 401II. Effect of Water Hardness 402A. Builders 402B. LSDAs 404III. Fabric Softeners 405IV. The Relation of the Chemical Structure of the Surfactant to its Detergency 407A. Effect of Soil and Substrate 4071. Oily Soil 4072. Particulate Soil 4093. Mixed Soil 410B. Effect of the Hydrophobic Group of the Surfactant 411C. Effect of the Hydrophilic Group of the Surfactant 412D. Dry Cleaning 414V. Biosurfactants and Enzymes in Detergent Formulations 415VI. Nanodetergents (see Chapter 14, Section IIIF) 416References 416Problems 41911 Molecular Interactions and Synergism in Mixtures of Two Surfactants 421I. E valuation of Molecular Interaction Parameters 422A. Notes on the Use of Equations 11.1–11.4 423II. Effect of Chemical Structure and Molecular Environment on Molecular Interaction Parameters 427III. Conditions for the Existence of Synergism 440A. Synergism or Antagonism (Negative Synergism) in Surface or Interfacial Tension Reduction Efficiency 441B. Synergism or Antagonism (Negative Synergism) in Mixed Micelle Formation in an Aqueous Medium 442C. Synergism or Antagonism (Negative Synergism) in Surface or Interfacial Tension Reduction Effectiveness 445D. Selection of Surfactant Pairs for Optimal Interfacial Properties 447IV. The Relation between Synergism in Fundamental Surface Properties and Synergism in Surfactant Applications 448References 453Problems 45612 Gemini Surfactants 458I. Fundamental Properties 459II. Interaction with Other Surfactants 463III. Performance Properties 466References 467Problems 47013 Surfactants in Biology 471I. Biosurfactants and Their Application Areas 471II. Cell Membranes 480III. Surfactants in Cell Lysis 486IV. Protein Denaturing and Electrophoresis with Surfactants 491V. Pulmonary Surfactants 491VI. Surfactants in Biotechnology 493A. Mineral Engineering 494B. Fermentation 495C. Enzymatic Deinking 495D. EOR and Oil Bioremediation 495E. Enzyme Activity in Surfactant Media 496F. Carbon Dioxide “Fixing” in Bioreactors 496G. Soil Remediation 496H. Effluent Purification 497I. Surfactants in Horticulture 497J. Vesicle Manipulation 497K. Genetic Engineering and Gene Therapy 497References 498Problems 50114 Surfactants in Nanotechnology 502I. Special Effects of the Nanostate 503II. Role of Surfactants in the Preparation of Nanostructures 503A. Bottom-Up Methods 5041. Surfactant Self-Assembly 5042. Synthetic Processes 508B. Top-Down Methods 517III. Surfactants in Nanotechnology Applications 517A. Nanomotors 517B. Other Nanodevices 520C. Drug Delivery 522D. Nanostructural Architectural Control of Materials 522E. Nanotubes 525F. Nanodetergents 525G. Surfactant Nanoassemblies in the Origin of Life 526References 528Problems 52915 Surfactants and Molecular Modeling 531I. Molecular Mechanics Methods 533A. Parametrization from Experiments 534B. Classes of FF Methods 534II. Quantum Mechanical Methods 534A. Application to the Electronic Problem 536B. The Hartree Product (HP) Description 537C. Minimal and Larger Basis Sets 538D. Electron Correlation Method 539E. Density Functional Theory (DFT) 540III. Energy Minimization Procedure 540IV. Computer Simulation Methods 541V. Surfactant Systems 542VI. Five Selected Systems 542A. Aggregation in a Liquid (i) 542B. Aggregation in a Liquid (ii) 543C. Liquid–liquid and Liquid–Gas Interface 545D. Solid–Liquid Interface 547E. Solid–Liquid Interface and Aggregation in a Liquid 549VII. Summary of Representative Modeling Studies 550General References 568Problems 568Answers to Selected Problems 569Index 576

“Written by Milton J. Rosen and Joy T. Kunjappu, two leading authorities in the field, Surfactants and Interfacial Phenomena, Fourth Edition is an unparalleled tool for understanding and applying the latest information on surfactants, and includes unique data tables and end-of-chapter problems designed to enhance the reader’s understanding.”  (Chimie Nouvelle, 1 March 2013)“The book is recommended to all who want to enter the interesting and yet further growing field of surfactants at interfaces.  It can serve as textbook for graduated students attending courses on surfactants and their applications. The book is also excellent for experts working in fundamental and applied research as they can find the main principles of the modification of interfaces via the impact of surfactants.”  (Tenside Surfactants Detergents, 1 May 2012)