ABSTRACT
I. Introduction 296 II. General Theoretical Considerations 297
A. The origin of self-assembly 297 B. Factors determining the cmc 298 C. ITC measurements, major findings, and interpretation 300 D. Enthalpy associated with dissolving hydrocarbons 301 E. The enthalpy of micelle formation 303
III. Experimental Titration Protocols, Procedures, and Interpretation of Data 305 A. Determination of the heat evolution of the
self-assembly of surfactants 305 B. Partitioning of solutes between membranes and
aqueous solutions 309 C. The heat evolution of bilayer-micelle phase
transformation in mixtures of phospholipids and detergents 312 IV. Heat Evolution of the Transfer of Amphiphilic Molecules
Between Aggregates and Water 316 A. Heat of micellization and its dependence on
temperature and composition 316 B. Heat of partitioning of amphiphiles between lipid bilayers
and aqueous media 321 C. Heat of phase transformations in mixtures of
bilayer-forming and micelle-forming amphiphiles 328 V. Concluding Remarks 331
References 332
I. INTRODUCTION A common feature of all amphiphiles is their tendency to self-assemble in aqueous solutions above a critical concentration, denoted as the critical aggregation concentration or, for micelle-forming amphiphiles (surfactants), the critical micellar concentration, abbreviated cmc [1-3]. The structure of the resultant aggregates depends on the molecular geometry of the amphiphiles and varies from micelles of various geometries (e.g., spheres, ellipsoids, or rods) to bilayers, cubic, or hexagonal phases [4,5].
