The critical micelle concentration CMC of sodium dodecyl sulfate SDS in water at 30C is approximately 8.2 mM millimolar . The CMC is the concentration of surfactant molecules above which micelles start to form spontaneously. Below the CMC, the surfactant molecules remain as individual molecules in the solution.Micelles are aggregates of surfactant molecules that form when the concentration of surfactant molecules in a solution exceeds the CMC. In the case of SDS, the micelles are spherical in shape, with the hydrophobic tails of the SDS molecules pointing towards the center of the micelle and the hydrophilic head groups facing the surrounding water.There are several factors that affect the formation of micelles and the CMC of SDS:1. Temperature: The CMC of SDS decreases with increasing temperature. This is because the hydrophobic effect, which drives micelle formation, becomes stronger at higher temperatures. At 30C, the CMC of SDS is around 8.2 mM, while at 25C, it is around 8.7 mM.2. Presence of salts: The addition of salts to the solution can affect the CMC of SDS. In general, the presence of salts decreases the CMC, as the salts can shield the electrostatic repulsion between the negatively charged head groups of SDS molecules, making it easier for the molecules to aggregate into micelles.3. pH: The CMC of SDS can also be affected by the pH of the solution. At very low pH, the negatively charged sulfate head groups of SDS can become protonated, reducing the electrostatic repulsion between the head groups and lowering the CMC. However, at the typical pH range of water, the effect of pH on the CMC of SDS is minimal.4. Presence of other surfactants or solutes: The presence of other surfactants or solutes in the solution can also affect the CMC of SDS. For example, the addition of a nonionic surfactant can lower the CMC of SDS, as the nonionic surfactant can interact with the SDS molecules and reduce the repulsion between the head groups.In summary, the CMC of SDS in water at 30C is approximately 8.2 mM. The formation of micelles and the CMC of SDS are influenced by factors such as temperature, presence of salts, pH, and the presence of other surfactants or solutes in the solution.