In recent months, we have taken an in-depth look at the structure and properties of cationic and nonionic surfactants. Another interesting category of surfactants used in both hair and skin care are the zwitterionic ones, those that naturally have two charges on the molecule, both positive and negative. These are attractive to the formulator due to their tendency to boost effects of other surfactants in the solution, as well as an ability to ameliorate undesirable properties of some surfactants, such as skin irritation and a tendency to strip the hair and skin of too much moisture. One familiar surfactant of this type is cocamidopropyl betaine, which is appreciated by many curly-haired consumers for its gentle, yet effective, cleansing capabilities.
What are they?