Cationic surfactant
Positively charged, so it sticks to fabric and to most surfaces rather than rinsing away. That is the point of it, and the problem with it.
In detail
A cationic surfactant carries a positive charge. Most textiles, hair and hard surfaces carry a slight negative charge in water, so a cationic is attracted to them and deposits rather than rinsing off. Almost every use of the class follows from that: fabric conditioners work by leaving a cationic film on the fibre, and many disinfectants are cationic because the same affinity brings them onto the surface where they need to act. It also explains the class's chief incompatibility. A cationic and an anionic in the same water will find each other and form a complex that neither cleans nor conditions — which is why conditioner goes in a separate dispenser and is released after the detergent has gone. Declared on a label by class and weight band above 0.2%.
Why
- Cationic surfactant is explained by Surfactancy
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 cationic surfactants carry a positive charge, substantively deposit on negatively charged surfaces and fibres, and are incompatible with anionic surfactants. (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 .