3

I. Introduction .................................................................. 77 II. Surfactant Exchange and Micelle

Formation/Breakdown: Theoretical Aspects ............... 81 A. Aniansson and Wall Theory of Micellar

Kinetics .................................................................... 81 1. Basic Assumptions........................................... 81 2. Relaxation Time for the Exchange Process ... 84 3. Relaxation Time for the Micelle

Formation/Breakdown ..................................... 86 B. Extension of the Theory to Ionic Surfactants

with or without Added Salt .................................. 87 1. Exchange Process ............................................ 87 2. Micelle Formation/Breakdown........................ 89

C. Relaxation Amplitudes.......................................... 91 D. Extension to Mixed Micelles................................. 92

E. Other Theoretical Treatments of Micellar Kinetics .................................................................. 93

III. Surfactant Exchange and Micelle Formation/Breakdown: Experimental Aspects........... 94 A. General Observations............................................ 94 B. Information Gained from Studies of the

Exchange Process ................................................. 101 C. Information Gained from Studies of the

Micelle Formation/Breakdown............................. 110 D. Dynamics of Giant Micelles................................. 113

IV. Dynamics of Aqueous Mixed Micellar Solutions ...... 115 A. Preliminary Remarks........................................... 115 B. Mixed Systems with Two Surfactants ................ 116 C. Mixed Systems with One Surfactant and

One Cosurfactant.................................................. 118 1. Studies of Surfactant and Cosurfactant

Exchanges ....................................................... 119 2. Studies of the Formation/Breakdown of

the Mixed Cosurfactant/Surfactant Micelles............................................................ 121

V. Dynamics of Solubilized Systems .............................. 124 A. Rate Constants for the Exchange of the

Solubilizate ........................................................... 124 B. Effect of Solubilizates on the Micelle

Dynamics............................................................... 129 VI. Dynamics of Polymer/Surfactant Systems ................ 130

A. Reminder on Polymer/Surfactant Systems......... 130 B. Surfactant Exchange from Polymer-Bound

Micelles.................................................................. 132 C. Kinetics of Formation/Breakdown of

Polymer-Bound Micelles....................................... 136 D. Miscellaneous Studies .......................................... 138

VII. Dynamics of Various Processes Occurring in Micellar Systems ......................................................... 138 A. Counterion Exchange Kinetics ............................ 138 B. Micellar Kinetics at the Approach of a

Critical Point......................................................... 140 C. Micellar Kinetics in the Presence of

Cyclodextrins ........................................................ 141

D. Dynamic Surface Tension and Micelle Formation/Breakdown Kinetics ........................... 142

VIII. Relevance of Micellar Kinetics to Practical Aspects of Surfactant Solutions ................................. 143

IX. Conclusions and Summary ......................................... 143 References............................................................................. 146

I. INTRODUCTION

In aqueous solutions, surfactants self-associate into micelles at a concentration above the critical micellization concentration (cmc). The formation of micelles is a cooperative process that is well described by the mass action law. Micelles can be considered as chemical species that are in equilibrium with free (nonmicellized) surfactant. These various aspects are briefly reviewed in Chapter 1.