An APEO-free*, solvent-free*, hydrophobically-modified alkali-soluble (HASE) rheology modifier for waterborne architectural coatings. The product can be used to build viscosity in the low, medium, and high-shear range as an alternative to cellulosic thickeners, offering better film build, better leveling, and easier incorporation into coatings than cellulosic thickeners. It is supplied as a low viscosity liquid that is easy to handle and incorporate during the manufacturing process.