Low foaming surfactant systems for industrial applications

In many applications the surfactant system has to meet contradicting physical requirements. The surfactants should provide not only excellent cleaning performance but additionally exhibit low foaming properties. However, the same physical parameters that need to be adjusted to ensure effective wetting power are on the other hand responsible for the effective formation and stabilization of foam. A good basis for a deeper understanding of foaming behavior offer phase behavior studies. In the case of alcohol ethoxylates a lot of those studies exist and the connection between the water solubility, the cloud point phenomena and the foaming behavior is generally recognized. However, the situation is more complex in the case of the alcohol EO-PO adducts, which are empirically recognized as low foaming agents. Up to now there is no coherent set of physico-chemical studies to provide a basic understanding of the low foaming behavior. This presentation gives some insight into the principles lying behind the foaming action of surfactants and compares the physico-chemical charac teristics of alcohol ethoxylates and E0-P0 adducts. The results can give the formulator guidance for selecting low foaming surfactant for more demanding applications.