Triethanolamine is a clear, colorless and highly viscous liquid.
Its chemical structure includes a tertiary amine, or a nitrogen atom with three carbon groups attached, and three alcohol groups one on the end of each carbon group.
When a nitrogen atom has made three bonds, it is left with a single pair of electrons that contain a partially negative charge, which makes the pair of electrons ready to make a bond with a positively charged atom.
The trait of having a partially negative pair of electrons available to make a bond makes a molecule basic, or alkaline. Therefore, triethanolamine is a base, which means the pH of this ingredient, when added to water at low concentrations, is very high. For this reason, triethanolamine makes an excellent pH adjuster.
When it is necessary to neutralize an acidic solution or to generally increase the pH of a product, triethanolamine is a common choice. It is often chosen over other bases, such as potassium hydroxide, because it is not as powerful of a base, and therefore, it allows any base-driven reactions to occur more steadily.
One instance where triethanolamine is useful is in activating the water-swellable polymer known as hydroxyethylcellulose. This normally holds a neutral pH in water, but in order to swell and thicken the water to a gel, triethanolamine is added to increase the pH to the required 9.0 to 9.5.