Micelles and the critical micelle concentration CMC

1. Micelles and the critical micelle concentration (CMC) At low concentrations of soap, surfactant molecules exist in solution as monomers (individual molecules of surfactant). When a hydrophobic dye is added to this solution, the dye settles to the bottom and has little solubility At higher concentrations of soap, the surfactant molecules saturate the surface and start forming aggregates in solution called micelles (micelles are formed once the soap/surfactant exceeds a given concentration called the critical micelle concentration, CMC). These micelles have a hydrophobic (oil-loving) core which can solubilize a hydrophobic dye. Thus when the dye is added to this solution, it is solubilized and results in a vivid change in the color of solution. This is the same type of mechanism which causes detergents and soaps to remove oil and grease stains from your dishes or clothes.

2. CMC Explanation The core of a micelle is hydrophobic and can solubilize a hydrophobic dye