One-Step Synthesis of Poly(amide ester)-Based Block Copolymers with Defined Phase Separation Behavior

We developed a self-switchable, one-step polymerization system based on N-tosylaziridine (TAz)/cyclic anhydride ring-opening copolymerization (ROCOP), cyclic carbonate ring-opening polymerization (ROP), and epoxide/anhydride ROCOP. This system uses a phosphazene-based catalyst for the synthesis of chemical structurally diverse block copolymers. “Block-like” poly(amide ester)s were synthesized by combining two catalytic cycles of TAz/anhydride ROCOP. “Real” block poly(amide ester)-b-polycarbonate and poly(amide ester)-b-polyester were then synthesized by combining TAz/anhydride ROCOP with cyclic carbonate ROP and epoxide/anhydride ROCOP, respectively. Differential scanning calorimetry revealed two glass transition temperatures for the “real” block copolymers, and small-angle X-ray scattering measurements confirmed microphase separation, illustrating a significant difference in polarity between the two blocks of copolymers. These results confirm the precise control of the chemical structure and properties of each block on the synthesized copolymers. This method also enables the comprehensive and synchronous adjustment of the chemical structures of copolymer blocks, a challenge that has received much attention in the field of copolymer synthesis.