An anionic surfactant is a sulfonic acid (negative charge) and a cationic surfactant is a quaternary salt (positive charge). I know what you are saying, but just as in the definition of emulsion vs dispersion, I refer to them in the book and in my own mind this way. It is due to the way that electronics people and chemists think I guess.

See this: http://en.wikipedia.org/wiki/Ion

or this: http://en.wikipedia.org/wiki/Anode

Which explains my reason for the definition and also the confusion around these terms.

PE