Why do we care about surfactant precipitation? Because precipitated surfactant is surfactant that isn’t changing the properties of a surface or interface. We almost always want to eliminate precipitation from our surfactant systems. The only exception is when we are looking to remove the surfactant from solution, as might occur in waste water treatment or a separation process.
For ionic surfactants there is no property that is more important than the Krafft temperature of the surfactant. The Krafft temperature is the minimum temperature at which the solubility of the surfactant monomer becomes high enough for the surfactant to start to form micelles. In general, surfactants are inactive below their Krafft temperature. Mixtures of surfactants can be used to lower the Krafft point of a surfactant formulation. This is a key approach to improving the performance of a formulation in both accelerated aging chambers and in freeze-thaw cycles. In our short course we will show you how to use this information to avoid a nasty surprise that surfactants have been known to spring on the unwary technologist: Salt shock! It’s not toxic shock, but it’s close!