Supramolecular transparent plastic engineering via covalent-and-supramolecular polymerization

Abstract

Supramolecular glass and plastic are a new generation of artificial transparent materials that exhibit excellent optical behavior and processability. However, owing to inherent deficiencies in their mechanical toughness and long-term stability, supramolecular materials lack the potential for functionalization and application. Inspired by the toughening phenomena in biological systems, a synergistic covalent-and-supramolecular polymerization strategy was applied to construct plastic-like supramolecular materials with high transmittance via the solvent-free one-pot amidation of thioctic acid and (poly)amines. Covalent amide linkers, dynamic disulfide bonds, and hydrogen bonds significantly enhance the mechanical toughness and hardness of supramolecular plastic. Greatly benefitting from covalent-and-supramolecular polymerization, not only does the supramolecular plastic exhibit a high mechanical strength of 45.51 MPa and a rigidity of 74.0 HD, but it is also highly resistant to mechanical impact (34.47 kJ m⁻²). Experimental and theoretical investigations demonstrated that polymeric structures connected via amide units are responsible for the tough mechanical properties, whereas the dynamic and reversible bonding/debonding of disulfide and hydrogen bonds favor energy dissipation, which together convert supramolecular transparent plastic into a rigid and tough material.