These are the main chemicals in the everyday formulations that form the basis of this book and, as such, are discussed at length in Chapter 2. Very briefly, surfactants are the most versatile of chemicals found in modern formulations and carry out functions such as: emulsification, detergency, wetting and spreading, solubilizing, foaming and defoaming, lubricity, biocidal, anti-static and corrosion inhibition.

For convenience, surfactants are grouped on the basis of their molecular types rather than functionality. The groups are: non-ionic, anionic, cationic and amphoteric. Within each category we may find that a range of functions is represented and that individual molecules can carry out a variety of tasks but with different degrees of effectiveness to related molecules.