Platonic Micelles and Conventional Surfactant Micelles: Comparison and Contrasts

Conventional surfactants form micelles with a distribution of sizes, which may be narrow or broad. Most of the hydrophobic surface area of the surfactant tails is removed from contact with water since that constitutes the driving force for surfactant self-assembly. In contrast, for aggregates formed from calix(n)arne amphiphiles, also referred to as Platonic micelles in the recent literature, the aggregation numbers are discrete, making them structurally precise analogous to a multi-subunit protein. In these aggregates a vast fraction of the hydrophobic surface area of the tails remains in contact with water even after the formation of the aggregates. In this talk I will present a structural and energetic description of these structurally precise aggregates in order to rationalize their contrasting properties. The analysis also reveals the importance of the tail in determining the structural precision, compared to that of the head, as visualized in the Platonic structural models.