Self-Healing Thermoplastic Elastomers Formed from Triblock Copolymers with Dense 1,2,3-Triazole Blocks

Expanding the range of strong and self-healable polymer networks is of fundamental interest and practical importance. In this work, we report a network of poly­(3-azido-1-propyne)-block-poly­(ethylene glycol)-block-poly­(3-azido-1-propyne) (APn-b-EGm-b-APn, where m and n denote the degrees of polymerization) triblock copolymer prepared by the modular copper­(I)-catalyzed azide–alkyne cycloaddition (CuAAC) polymerization of AP in the presence of alkyne-functionalized EGm. The presence of dense 1,2,3-triazole-containing blocks promotes a microphase-separated structure that provides the network structure elasticity even though the number-average molecular weight is rather low (ca. 4.6 × 103). The fracture stress and strain of the network reach ca. 7.2 MPa and 550% strain at 25 °C. On the other hand, the dense 1,2,3-triazole moieties in the APn block provide efficient supramolecular interactions that enable self-healing after fracture. The full-cut fractured networks reached ca. 80% recovery of strain and recovered tensile strength to 2.4 MPa after healing at 55 °C for 24 h.