Combining Multiple Supramolecular Interactions and Thiol-ene Photopolymerisation for Biobased Self-healing and Chemically Weldable Polymers Containing Amino Acids

Abstract Self-healing polymers can be achieved through several intrinsic mechanisms, including supramolecular interactions (e.g., ionic, hydrogen bonding, π-π stacking) and dynamic covalent crosslinking. Herein, we combine multiple mechanisms to a series of biobased unsaturated poly(ester amide) oligomers, prepared using α-amino acids (4-aminobutyric acid, L-phenylalanine, or para-aminobenzoic acid) and succinic anhydride, sodium 2,3-dicarboxypropane-1-sulfonate prepared from itaconic acid, carbic anhydride, and 1,4-butanediol. The oligomers were photopolymerised by thiol-ene crosslinking using PETMP, yielding crosslinked polymers with properties that could be tailored by strategic choice of amino acid structure and mechanical properties similar to several biological tissues, with Young’s moduli of 0.16–2.38 MPa, ultimate tensile strength of 0.27–0.64 MPa, and elongation at break of 66–170%. The polymers displayed vitrimer qualities with self-healing through thermal treatment at 130 °C, and fractured specimens could be healed with mechanical properties similar, or even superior to, the fresh specimens. Chemical welding of the crosslinked polymers could also be performed to create multi-material components. Lastly, the polymers displayed controlled degradation in phosphate buffered saline solution at 37 °C. Herein, we demonstrated that biobased platform molecules could be readily leveraged within facile synthesis strategies to yield tailorable polymers with both desirable properties and that undergo efficient self-healing and chemical welding.