The critical micelle concentration CMC of sodium dodecyl sulfate SDS at a temperature of 25C in water is approximately 8.2 mM millimolar . The CMC is the concentration at which surfactant molecules, such as SDS, begin to aggregate and form micelles in a solution.The CMC can vary with temperature. Generally, as the temperature increases, the CMC decreases. This is because the increased thermal energy allows the surfactant molecules to overcome the repulsive forces between their hydrophilic head groups more easily, leading to micelle formation at lower concentrations.Micelles are spherical aggregates of surfactant molecules, such as SDS, in a solution. They form when the concentration of surfactant molecules exceeds the CMC. In a micelle, the hydrophobic tails of the surfactant molecules are oriented towards the center of the sphere, while the hydrophilic head groups face the surrounding water. This arrangement minimizes the contact between the hydrophobic tails and water, which is energetically unfavorable.Micelles play a crucial role in soap solutions and detergents. When soap is added to water, it forms micelles that can solubilize hydrophobic dirt and grease particles. The hydrophobic tails of the soap molecules interact with the dirt or grease, while the hydrophilic head groups remain in contact with the water. The dirt or grease becomes trapped within the micelle, allowing it to be washed away with the water. This process is known as emulsification and is the primary mechanism by which soap and detergents clean surfaces.