ABSTRACT
Foam is often regarded by consumers as a beneficial aspect of detergent product performance. In the case, for example, of washing textiles or dishes by hand, the presence of foam is considered to be both an indication of cleaning effectiveness and a contribution to any aesthetic appeal associated with those activities. It would, however, seem that the former only has a firm basis in physical reality when phase separation of the surfactant as a result of interaction with polyvalent water hardness ions (to form crystalline or liquid crystalline entities) means that much of that ingredient is essentially not available for either cleaning action or foam generation. Use of certain surfactant types and surfactant mixtures together with various chelating agents (“builders”) in modern laundry products minimizes such effects and thereby minimizes any clear correlation between high foam and efficient detergency. This is fortunate because a large proportion of the market for detergent products for washing textiles or dishes consists of consumers who use foam-intolerant washing machines.
