Free-radical polymerization of styrene in worm-like micelles

The solubilization of styrene in wormlike micelles of the cationic surfactant, cetyltrimethylammonium tosilate (CTAT), and its polymerization is examined here by UV spectroscopy, oscillatory rheometry, small angle X-ray scattering, polarizing light microscopy, and transmission electron microscopy. At low CTAT concentrations, the polymerization of styrene yields small and rigid rods in coexistence with wormlike micelles that form from the excess surfactant after the polymerization process. At high CTAT concentrations, polymeric rods (of large aspect ratio), spheroid polymer particles, and wormlike micelles coexist. The polymerization rate is second order, indicating that polymerization reactions end mainly by bimolecular termination.