> [!Definition] > Micelles form only when the concentration of [[surfactants]] is greater than the CMC ![[5E2EE6FB-64BF-4EB1-8F4F-3A563DCEBC21.jpeg]] ![[EA5573EC-3EAC-45EA-BE22-F19B1F7D16F9.jpeg]] ## Best practices for detergents > https://technotes.alconox.com/industry/pharmaceutical/critical-micelle-concentration-detergent ### Use surfactants in excess of the CMC to guarantee cleaning capacity - [[Alconox]] Inc. detergents are typically recommended for use at **4 times** higher concentration than the theoretical CMC - ensure there are available micelles and cleaning capacity - ensure the ability to form new micelles as micelles are filled up with emulsified oils ### Stay closer to the CMC to minimize rinsing away of excess detergent - For light duty cleaning, you could use **1/4** the recommended dose - For difficult to rinse applications (ex: filter cleaning), you could use **1/2 - 3/4** the recommended dose - still gives you some excess concentration of detergent above the CMC, but leaves less detergent that needs to be rinsed away ## Determining CMC ### CMC varies with electrolyte and residue content of solutions.  - generally decreases as micelles shift from globes to rods in a more hexagonal arrangement in response to electrolyte content ### CMC of mixtures - CMC of the individual surfactants is sometimes known at 25°C in DI water - Mixed micelle CMC can be experimentally derived for any specific set of conditions - In general, a mixed micelle CMC will be **lower than the average of the CMC of the constituent surfactants**