The present invention provides polymer nanoparticles with a controlled architecture of nano-necklace, nano-cylinder, nano-ellipsoid, or nano-sphere. The polymer nanoparticle comprises a core polymerized from multiple-vinyl-substituted aromatic hydrocarbons, a shell polymerized from alkyl-substituted styrene, and a polystyrene layer between the core and the shell. The present invention also provides a method of preparing the polymer nanoparticles and a rubber article such as a tire manufactured from a formulation comprising the polymer nanoparticles.