Exact phenomenological interpretation of the micelle point in multi-component systems

Abstract

The definition of the micelle point or critical micelle concentration (CMC) in multi-component systems is discussed and an exact phenomenological analysis of the micelle point is given. It is shown that in most cases where it is meaningful the micelle point can be regarded as the transition point for a second order phase transition in a multi component system. Expressions are presented for the mutual dependences of temperature, pressure and composition of a system at its micelle point. The Krafft point is also considered but in less detail and some experimental data are discussed.

The methods developed can be applied to a smeared out phase transition of any order in a multicomponent system and to the behaviour of any physical property which changes sharply in a narrow region of the state variables.