Polymerization-Induced Self-Assembly for the Synthesis of Poly(N,N-dimethylacrylamide)-b-Poly(4-tert-butoxystyrene) Particles with Inverse Bicontinuous Phases.

Polymerization-induced self-assembly (PISA) has been routinely used to produce block copolymer (BCP) particles with various morphologies, but inverse bicontinuous phases have remained scarce. Herein, PISA preparation of poly(N,N-dimethylacrylamide-b-poly(4-tert-butoxystyrene) (PDMA-b-PtBOS) BCP particles with inverse bicontinuous phases in ethanol/water at 30% w/v solid content is reported. The effect of solvent composition and degree of polymerization of the core-forming PtBOS block is investigated. tBOS monomer conversion is enhanced on increasing water content, and inverse bicontinuous phases are effectively produced using a short PDMA stabilizer block. Morphology studies by both transmission and scanning electron microscopies reveal that transitions from vesicles to compound vesicles to inverse bicontinuous phases are the key mechanistic steps toward the formation of (partially) ordered mesophases.