A foaming agent is a chemical compound which facilitates the formation of foam or helps foam maintain its integrity by strengthening individual foam bubbles. Foaming agents are used in many industrial processes, and also around the home. In fact, chances are high that you came into contact with a foaming agent at some point today, perhaps while washing the dishes, preparing a load of laundry, or washing your hair.
A broad spectrum of chemicals can act as foaming agents. In all cases, they act as surfactants, reducing surface tension. Foaming agents are often packaged with products which are supposed to foam, such as detergent, activating when the detergent is released to promote the formation of foam and to keep the foam together. It is also possible to add such agents to materials while they are being processed, as seen when metal foams are produced in metalworking applications.
Different foaming agents are more effective for different materials, and chemists are often developing new products which can be used to produce foam. Some foaming agents have been criticized for toxic components which make them unsafe to use, leading to concerns about products made with these agents. A foaming agent also needs to be used with care even when it's nontoxic; in a classic example of a foaming agent gone awry, some people have learned the hard way that regular dish soap does not work in a dishwasher.
In industry, foaming agents are used whenever a foam needs to be created or when a suspension of ingredients is being prepared in the form of a foam. In the oil industry, for example, a specialty product known as drilling foam is sometimes used during drilling and oil exploration. Foams are also used in industrial cleaning applications, the preparation of building materials, and a wide range of other tasks. Such agents typically are used sparingly, as a little bit of surfactant goes a long way.
The composition of the foaming agent can have an impact on the integrity of a foam. Some foams tend to be very stiff and firm, with bubbles which have extremely strong walls. Others are softer, running together and collapsing over time. Different properties can be brought out with the selection of an appropriate foaming agent. For example, toothpaste is often formulated to have a soft foam, while some detergents have very stiff foams to ensure that they fully cover when they are used in cleaning.