The present invention pertains to new alkali swellable thickening emulsions, free of surfactants and solvents other than water: as a result, all drawbacks related to the use of solvents, or to the formation of foam in the case of surfactants, are avoided. These new emulsions contain a certain quantity of 2-acrylamido-2-methylpropane sulfonic acid (or AMPS, CAS #: 40623-75-4). They have proven effective at thickening aqueous mediums, particularly water-based paints, paper coatings, aqueous suspensions of mineral materials, detergents, cosmetic formulations, or formulations containing a hydraulic binder.
