Organocatalytic Precision Synthesis of Poly(ester amide)s with Enhanced Thermal Performance and Programmable Microarchitectures

Sequence-controlled polymerization, a precision technique enabling programmed arrangement of chemically distinct monomer units during copolymerization, establishes a versatile platform for engineering polymer architectures with tailored functionalities and unlocking unprecedented possibilities in advanced materials development. The ring-opening copolymerization of aziridines with cyclic anhydrides emerges as a particularly promising strategy for synthesizing sequence-regulated polymers through the alternating chain growth mechanism. Herein, we present a novel catalytic system employing organic ammonium salts to mediate the copolymerization of N-benzyloxycarbonyl (Cbz)-functionalized aziridines with cyclic anhydrides under mild conditions, yielding linear poly(ester amide)s (PEAs) with exceptional structural control. The electron-withdrawing Cbz-group effectively delocalizes the nitrogen lone pair electrons, suppressing ring-nitrogen nucleophilicity to ensure the formation of perfectly alternating copolymers with narrow molecular weight distributions. Strategic deprotection of the synthesized copolymers yields semicrystalline materials. Capitalizing on inherent monomer reaction activity, we demonstrate architectural control in terpolymer systems through continuous modulation from block-like to random chain sequences. This methodology enables the precise engineering of advanced PEAs through molecular architecture design, featuring programmable sequence control and predictable structure–property relationships that govern material performance characteristics.