Importance of Micellar Lifetime and Sub-micellar Aggregates in Detergency Processes

Micelles are known to be dynamic entities, rapidly breaking and reforming continuously. Micellar dynamics can be manipulated by the addition of non-ionic or oppositely charged cosurfactant to a sodium dodecyl sulfate solution. Using filtration through nanoporous membranes we have shown that sodium dodecyl sulfate micellar solutions are not only made up of micelles and monomers, but also contain a high concentration of sub-micellar aggregates. The concentration of sub-micellar aggregates decreases as the micellar stability increases. We have investigated the role of micellar stability and sub-micellar aggregates in cleaning of fabrics and hard surfaces such as porcelain dishes. After careful observation, it was determined that more stable micelles and lower concentrations of sub-micellar aggregates lead to more efficient detergency. In summary, it is desirable to have relatively stable micelles and the least number of sub-micellar aggregates for efficient detergency.