Hetero-Furan Unit Drives a Spontaneous Leaf-Vein Bioinspired Multiscale Design for Ultra-Robust, Lightweight, and Recyclable Polymers

Inspired by the interpenetrating network of nature leaf-vein, noncomposite polymer materials with ultra-robust, lightweight, and fully recyclable properties are synthesized by a hetero-furan unit-driven multiscale design. That is, starting from the primary chemical structure at the molecular scale, the furan group is copolymerized in a polymer chain (polyethylene terephthalate, PET). Then, these hetero-furan units simultaneously regulate the secondary chain conformation (nanoscale) and the tertiary aggregate structure (micro-scale) of the PET copolymer, thereby driving the spontaneous growth of the leaf-vein-mimicking crystal reinforcement phase. Requiring only less than 1% furan units, corresponding copolymer PET-FN1 not only exhibits surprising fourfold increase in toughness (tensile toughness of 346 MJ m(-3) and impact strength of 69.8 kJ m(-2)) and 40% increase in tensile strength (83.6 MPa) but also achieves lower density and easy processing. This demonstrates the super-efficiency of this bioinspired multiscale design regulated by the original chemical structure. Especially, copolymer PET-FN1 can be quickly chemically recovered under mild conditions (80 degrees C, 4 h) to obtain raw monomers with a purity of 99.8%. This work opens up a new perspective for developing advanced polymer materials with excellent mechanical properties, lightweight, and environmentally friendly recycling, which will greatly benefit the global circular economy and sustainable development.

Automated summary

Inspired by the interpenetrating network of nature leaf-veins, researchers have successfully synthesized noncomposite polymer materials with ultra-robust, lightweight, and fully recyclable properties. By designing the molecular structure of the polymer, they were able to control the secondary and tertiary structure of the material, resulting in the growth of a leaf-vein-mimicking crystal reinforcement phase. The resulting material exhibits exceptional mechanical properties, lower density, and easy processing. Additionally, it can be chemically recovered to obtain high-purity raw monomers.