A foam is a gas dispersed in liquid – similar to how an emulsion is a liquid dispersed in a liquid and a suspension is a solid dispersed in a liquid. Therefore, foams are similar to emulsions and suspensions in the way in which they need to be stabilised or destabilised.
Coalescence of bubbles is to be prevented if a stable foam is desired or is encouraged if a foam is to be killed. This can be compared to emulsification/demulsification and dispersion/coagulation. This is why our surfactants can play a key role in controlling foams throughout downstream, midstream and upstream processes.