Amphoteric surfactant
Changes its charge with the pH of the water around it. Used where mildness matters more than power.
In detail
An amphoteric surfactant can carry a positive or a negative charge depending on the pH of the solution it is in. That makes it unusually compatible: it will work alongside anionics and cationics that would otherwise react with one another, which is why it turns up as a secondary surfactant in a great many formulations rather than as the main one. Its other characteristic is mildness. The class is markedly less irritating to skin than a strong anionic at the same concentration, so it is the surfactant of choice in products designed for prolonged hand contact and in formulations aimed at sensitive skin. Declared on a label by class and weight band above 0.2%.
Why
- Amphoteric surfactant is explained by Surfactancy
- Amphoteric surfactant is explained by pH in cleaning
Sources for this page
Sources
Regulation (EC) No 648/2004 on detergents, Annex VII — labelling and ingredient data sheet
European Parliament and Council, as retained in UK law (legislation.gov.uk), 2004 · Government or regulator
Relied on for: That the class is one of the constituents a detergent label must declare, in weight bands above 0.2%. (states this directly)
Verification: a person has read the passage relied on.
Read on — Annex VII section A, the weight-range list and the declare-regardless list. Supports the claim as stated. Enumerates the ingredient-class family completely, and supplies the vocabulary a reader is actually confronted with on the back of a bottle.
Handbook of Detergents (Surfactant Science Series)
CRC Press / Taylor & Francis · Reference work
Relied on for: That amphoteric surfactants carry a charge that varies with pH, are compatible with both anionic and cationic surfactants, and are used for mildness. (background and mechanism only)
Verification: the work exists and is described correctly. Nobody has yet read the specific passage.
Last reviewed by a person on .