Probably the least talked about surfactants are the amphoterics. These unique molecules possess both a positive and a negative charge on their hydrophilic end, giving them a net charge of zero. Amphoteric surfactants have little utility on their own, but work extremely well in enhancing the cleaning effect of both anionic and nonionic surfactants. They can serve as “coupling agents,” which hold the surfactants, solvents and inorganic salt components of a formula together.
Amphoterics are usually named in some way to indicate that they are amphoterics, as in amphoterge. Other examples of amphoterics are betaines and amine oxides.
A Buffet of Chemistry
With all these different types of surfactants, and with a seemingly infinite list of each type of surfactant, it is a wonder that formulators are able to choose the right detergent for the right application. Experienced formulators have gotten their hands dirty working with many different types of detergents in an effort to make just the right blend of cleaning agents. Any formulator worth his salt will be quick to tell you that not all surfactants are created equal, and that some cleaners are better than others, given the situation.