Typically ammonia is used due to the cost, but other amines will work well, including triethyl amine. Amines that are high boiling-above the boiling point of water-should be avoided because they will remain in the film after the water leaves and may result in lower film strength due to lower chain entanglement. This problem is greater for acrylic waterborne coatings but is generally not a major problem for alkyds because their molecular weight is usually low and it crosslinks through air oxidation.
An amine emulsifier typically forms waterborne epoxy coatings. Usually the amine hardener acts as the surfactant through salt formation with added acetic acid. The epoxy is added to this emulsion and is soluble within the micelle. Once mixed, the amine begins to react with the epoxy and, usually within 30 minutes, the liquid micelle becomes a hard particle.