Synergistic engineering of poly(3-hydroxybutyrate) architecture and stereomicrostructure achieves enhanced material properties

Chemically engineering the stereomicrostructures of biodegradable poly(3-hydroxybutyrate) (P3HB) has been shown to be an effective strategy to largely modulate its properties for mono-material product design, but whether coupling this method with P3HB architecture engineering could yield an even more effective strategy has yet to be demonstrated. Here, through stereochemically and architecturally controlled polymerization, four-arm star-shaped P3HBs consisting of stereo-perfect isotactic, iso-rich, and syndio-rich stereomicrostructures, as well as their linear counterparts of comparable molar mass as controls, have been synthesized. Comprehensive and comparative characterization studies have uncovered various degrees of impacts of the P3HB architecture on thermal transitions, crystallization behaviors, mechanical performance, and rheological and gas barrier properties. In particular, coupling both stereomicrostructure and architecture engineering approaches has produced synergistically enhanced effects on the overall material properties, providing a more powerful strategy to design mono-materials with vastly different properties without changing their chemical composition.