Aspects of the Statistical Thermodynamics of Amphiphilic Solutions
Perhaps the most distinctive feature of solutions of amphiphilic molecules is that their microstructure depends sensitively on the bulk thermodynamic variables which specify the state of the system: Dilute solutions of surfactants are isotropic and homogeneous molecular dispersions, while micellar aggregates and a variety of liquid crystalline mesophases are encountered at progressively higher concentrations. Of particular interest in the present discussion is the interplay of self-association and phase equilibria, especially those involving the isotropic micellar phases which have been discussed extensively at this conference. In the following, we indicate some of the important conclusions of recent work in this area and highlight some fundamental open questions. The discussion below is divided into two sections, the first dealing with general aspects of phase equilibria in associating solutions, the second specializing to the neighborhood of second order phase transitions. A common theme here is the concept of effective interactions in micellar solutions, especially near critical points or points of rapidly changing microstructure.
KeywordsLower Critical Solution Temperature Micellar Solution Effective Interaction Consolute Point Thermodynamic Field
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