Abstract
Micorogels are classified as soluble intramolecularly cross-linked macromolecules, with the size less than 100nm. Unfortunately microgels have received less attention than other conventional linear or branched macromolecules, because they had formerly been impossible to be selectively produced in large amounts in a factory. In 1984, the microgels were successfully manufactured via an emulsion polymerization process involving the use of novel amphiphilic oligomers containing the zwitterion moiety as emulsifiers. Those oligomers differed from commercially available surfactants that failed to produce the microgels with properties such as long shelf stability, low viscosity, practical solid concentration and water resistance. This was the origin of the industrial production of microgels.
Since then, the application of the microgels as additives to coatings has been significantly accelerated. The mutual affinities between microgels and solution, polymer matrices or different particles result in the improvement of the performance of coatings. This includes the rheology of composition, dispersion of pigments, moisture permeability, aesthetic properties and transparency of coated films. The application besides coatings, such as the formation of void-containing Particles by the aid of microgels, are also discussed.
