Foam colloids are present in nearly every room of a typical home. Many common household products are made of foam colloids. Products made from this material are extremely versatile in application and can serve functions ranging from cleaning to structural support.
Defining a Foam Colloid
Matter typically takes one of three forms: solid, liquid or gas. A colloid is a substance formed from two differently phased materials combined to form a suspension. Each type of combination tends to exhibit different properties and have its own technical term. A suspension of air within a liquid is known as foam. A suspension of air within a solid medium is known as solid foam.
Properties of Foam Colloids
Solid foam colloids tend to be lightweight and are easily shaped into various forms. Depending on the rigidity of the material making up the solid matrix, a solid foam colloid may be stiff and firm, or pliable and yielding. Because of these properties, solid foams are often used in cushioning applications. The consistency of liquid foam colloids tends to vary depending on the ratio of liquid to gas in the suspension. The more air in a liquid foam colloid, the stiffer and less pliable the foam. If it contains a high liquid ratio, the foam may have difficulty holding a consistent shape. Liquid foams are particularly good at trapping particles within the matrix of the suspension, making them good candidates for use in surfactants.
Solid Foam Colloids
Styrofoam, perhaps the most familiar example of a solid foam colloid, is most often used as a packing material for shipping products long distances. Delicate equipment is often packaged and sold with molded polystyrene to stabilize the product. Solid foam is a low-cost filler material for pillows. Memory foam is used in high-end mattresses. Stiffer foams are used for light structural support. Because of the air distributed within the foam, solid foams make good material for insulation.
Liquid Foam Colloids
Laundry detergents, soaps, dishwashing liquid and many cleaning solvents form foams upon use. Examples include the lather that forms with the use of soap. This lather consists of liquid foam that uses the repulsive forces between the air and liquid phases of the foam to trap particles such as dirt and bacteria. Shaving creams are liquid foams that act in much the same matter except the captured particles are skin cells and hair clippings. Some foam colloids are edible, such as whipped cream or beaten egg whites. These edible colloids' pliability makes them well suited for decorative topping purposes as well as taste.
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