The critical micelle concentration CMC of sodium dodecyl sulfate SDS in water at room temperature 25C is approximately 8.2 mM millimolar .The addition of an electrolyte to the solution can affect the CMC of SDS. Generally, the presence of electrolytes can lower the CMC. This occurs because the added electrolyte ions can shield the repulsive forces between the charged head groups of the SDS molecules, allowing them to aggregate more easily and form micelles at lower concentrations.The extent to which the CMC is affected depends on the type and concentration of the electrolyte. For example, the addition of sodium chloride NaCl to the SDS solution will have a different effect than the addition of calcium chloride CaCl2 . In general, the higher the concentration of the electrolyte, the greater the reduction in CMC. However, the specific relationship between electrolyte concentration and CMC reduction will depend on the specific system being studied.