Synthesis, Supramolecular Assembly, and Hydrogelation of Poly(amino ester) ABA Triblock Copolymers

Poly(amino esters) derived from <i>N</i>-acylated-1,4-oxazepan-7-ones (OxPs) emerge as promising candidates in the development of new and degradable amphiphiles for hydrogel preparation and delivery formulations. Here, the synthesis of amphiphilic triblock copolymers by ring-opening copolymerization of OxP monomers with various pendant chains is reported. Copolymerization using organocatalysts and a bifunctional initiator afforded neutral P(OxP_Me)-<i>b</i>-P(OxP_Bn)-<i>b</i>-P(OxP_Me) and cationic P(OxP_NH2⁺)-<i>b</i>-P(OxP_Bn)-<i>b</i>-P(OxP_NH2⁺) amphiphilic triblock copolymers with controlled molar masses ranging from 4,600 to 8,500 g/mol and narrow dispersities (Đ ≤ 1.21). A panel of polymers with various block lengths and compositions was synthesized. Their self-assembly in water revealed the formation of nanostructures, including worm-like or spherical morphologies. Modulation of the copolymer composition and concentration enables control over hydrogelation and its macroscopic properties. Finally, we investigated the formulation of a hydrophobic fungicide and its inhibitory effect on spore proliferation, which shows great promise as dispensable and biodegradable hydrogel formulation for agrochemical applications.