ABSTRACT
In the history of mankind, the washing process is probably one of the oldest known systems that relates to surface chemistry. As known from experience, any physical property of a liquid will change when a substance (called a solute) is dissolved in it. Of course, the change may be small or large, depending on the concentration and other parameters. Accordingly, the magnitude of surface tension of a liquid will change when a solute is dissolved in it. This will be expected from physicochemical considerations. It also becomes apparent that if the surface tension of water could be manipulated, then many application areas would be drastically affected. In this chapter some important surface active substances with such properties will be described. These are some speci†c substances that are used to change the surface tension of water in order to apply this characteristic for some useful purpose in everyday life.
