Classification of Surfactants

Students learn to distinguish between anionic, cationic and non-ionic synthetic detergents in terms of:
- chemical composition
- uses

Surfactants are said to fall into four broad categories: anionic, cationic, nonionic, and zwitterionic. To help us understand the differences between these categories, we'll have a look at a number of different common surfactants and work out how to categorise them. As we go, we'll also have a look at how these different classes of surfactants are commonly used.

It is interesting to note that all of surfactants we will look at here are synthetic surfactants - even the simplest all the surfactants (soap) is in fact synthesised from natural products. Soaps such as sodium oleate are only a couple of synthesis steps away from the original natural products but nonetheless they are man-made.

The total US market for surfactants in 1993 was almost 5 × 109 kg, with a total value of $3.5 × 109. The size of this market makes for some quite competitive marketing and research. Between 1992 and 1994, around 1500 world patents were issued for cleaning products.

[Source: Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed, J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p. 297-326.]