Bioinspired Design and Synthesis of Polyphenolic Star-Like and Hyperbranched Polyester Models

Inspired by the structure of natural gallotannins, which feature polyphenolic galloyl ester chains grafted onto a glucopyranose core, we report the design and synthesis of star-like and dendritic hyperbranched aromatic polyester model compounds. Using penta-O-acylated-D-glucopyranose core molecules made from D-glucose and AB_n-type phenolic acid monomers, such as vanillic, protocatechuic, ferulic, and caffeic acids, we developed a modular strategy to access core-arm architectures through stepwise esterification reactions under mild Steglich conditions. Oligomeric model compounds were synthesized to validate this strategy and assess the solubility and structural features of the resulting materials. Direct polyesterification attempts yielded partially grafted analogues, and protocatechuic acid-derived polymers spontaneously formed stable aqueous dispersions with nanoparticulate structures (∼400 nm). These glycopolymeric nanoparticles were successfully loaded with the hydrophobic dye nile red, demonstrating their potential as bioinspired encapsulation systems. This work opens new perspectives for the development of functional biobased aromatic polyesters derived from renewable phenolics.