The swelling rate of latex polymer particles in seed coagulation was shown to be influential in determining the final morphology of the assembly of the latex particles. In the present work, droplets of various monomeric species were used as the coagulation seeds. The latex particles form assemblies by seed coagulation which starts on the surface of the monomer droplets. Assemblies with a dense shell formed when the latex particles swell with the monomer slowly enough to allow the latex particles to densely stack. The layer-by-layer immobilization of the latex particles proceeds without losing the spherical morphology of the individual assemblies. In this case, the final coagulation assembly is obtained as a spherically aggregated flock of the latex particles with a cavity in its center. On the other hand, the primary coagulation layer forms a monolithic hollow structure (shell) in the case where the latex particles on the monomer droplets entirely and rapidly swell before the second coagulation layer is completed. Subsequently, a sparse porous layer of the latex particles forms on the outer surface of primarily formed monolithic inner shell.