Solvent-induced micelle formation in a hydrophobic interaction model

TL;DR

This paper models solvent-induced micelle formation in amphiphilic molecules using an adapted water interaction model, revealing how hydrophobicity and tail length influence aggregation and critical solution temperatures.

Contribution

It introduces a refined two-state water model to explain micelle formation driven primarily by solvent effects, emphasizing the role of hydrophobic surface distribution.

Findings

Hydrophobicity significantly affects critical solution temperatures.

Longer hydrophobic tails stabilize lipid aggregates.

Micelle formation is mainly solvent-induced, explained by water structure alterations.

Abstract

We investigate the aggregation of amphiphilic molecules by adapting the two-state Muller-Lee-Graziano model for water, in which a solvent-induced hydrophobic interaction is included implicitly. We study the formation of various types of micelle as a function of the distribution of hydrophobic regions at the molecular surface. Successive substitution of non-polar surfaces by polar ones demonstrates the influence of hydrophobicity on the upper and lower critical solution temperatures. Aggregates of lipid molecules, described by a refinement of the model in which a hydrophobic tail of variable length interacts with different numbers of water molecules, are stabilized as the length of the tail increases. We demonstrate that the essential features of micelle formation are primarily solvent-induced, and are explained within a model which focuses only on the alteration of water structure in the vicinity of the hydrophobic surface regions of amphiphiles in solution.