A semibatch bromate-sulfite (B-S) pH oscillator is applied to drive the autonomous generation of polymersomes through polymerization induced self-assembly (pH-O-PISA) as a provider of radicals for polymerization of a hydrophobic monomer extending from a 2-sulfur hydrophilic macromolecular chain transfer agent (mCTA) to form an amphiphilic copolymer, and to regulate the morphological evolution of the self-assembled polymersomes.