The present invention relates to the use of surface-modified nanoparticles to alter the morphology and microstructure of polymer blends. The addition of surface modified nanoparticles to polymer blends comprised of immiscible polymers facilitates the uniform distribution of the dispersed phase of the polymer blend. In an embodiment, the present invention relates to a polymer blend comprising (1) a continuous phase comprising at least one polymer, monomer or oligomer, and a plurality of surface-modified nanoparticles, having a particle diameter of less than about 100 nanometers, distributed in the continuous polymer phase; and (2) a dispersed phase comprising at least one polymer, monomer or oligomer, wherein the continuous polymer phase and the dispersed polymer phase are immiscible.