Provided are improved coatings, polymeric dispersions, and polymeric composites, which include crosslinked polymeric nanoparticles (hereafter "PNPs"). Also provided are methods for forming improved coatings, polymeric dispersions, and polymeric composites, which include PNPs. The PNPs have polymerized units of at least one multi-ethylenically-unsaturated monomer have a mean diameter of from 1 to 50 nanometers. PNPs having polymerized units of at least one multi-ethylenically-unsaturated monomer and at least one surface-active monomer are also provided.