The present invention provides a composition comprising 1) an aqueous dispersion of polymer particles having a core-shell morphology wherein the core protuberates from the shell; wherein the core comprises from 5 to 90 weight percent structural units of a fluoroalkylated monomer, and 2) less than 0.09 weight percent structural units of a phosphorus acid monomer; and wherein the shell comprises from 0.1 to 5 weight percent of itaconic acid or a phosphorus acid monomer, based on the weight of the shell. The present invention addresses a need in the art by providing a way of selectively concentrating fluoroalkyl functionality into polymer particles with acorn morphology, thereby providing an improvement in dirt pick-up resistance of the subsequent coating.
