A Supramolecular Polymer Based on Tweezer-Type π-π Stacking Interactions: Molecular Design for Healability and Enhanced Toughness

A new polyamide with tweezer-type dipyrenyl end-groups was successfully synthesized. The new material differs from a related but mechanically much weaker blend solely in the strength of specified supramolecular interactions between the components, rather than in the chain-structures of the polymers themselves. The synthesis of polyamine involved reaction of Jeffamine 400 with isophthaloyl dichloride in the presence of ca. 20 mol% of the aminomethyl-substituted tweezer-molecue to end-cap the chains and control the degree of polymerization. The MALDI-ToF mass spectrum of polyamide exhibited well resolved signals consistent with the production of bis end-capped chains containing up to three Jeffamine 400 segments. The new material differs from a related but mechanically much weaker blend solely in the strength of specified supramolecular interactions between the components, rather than in the chain-structures of the polymers themselves. The results show that blend has an enhanced ultimate tensile strength and greatly increased modulus of toughness and elongation.