We here demonstrated a general, convenient and robust method to synthesize polymeric hemispherical shells through interfacial free-radical copolymerization using dynamic complex emulsion as template. The dynamic nature of complex emulsion template allowed the tunable synthesis from disk-like to hemispherical to truncated polymer shells. Attempts to take them out of solution resulted in their shrinkage in the solid state. These polymeric hemispherical shells were well-characterized by optical microscope, fluorescence microscopy and scanning electron microscopy (SEM). Furthermore, the formation of these hemispherical shells on complex emulsions changed the way they switch morphology upon external perturbation (e.g. adding additional hydrocarbon-water or fluorocarbon-water surfactant). The comparison between the regular phase diagram of a Janus droplet and the "modified" phase diagram of a Janus droplet with the polymer shell showed the confinement of droplet morphology in the Janus state. Future applications of these polymeric hemispherical shells include the fabrication of 2D lens array based on colloids and selective removal of heavy metal ions from waste water.