Functional and Environmental Friendly Polyimine Elastomer Based on the Dynamic Covalent Network for a Flexible Strain Sensor

With environmental concerns increasing, the development of durable, degradable, and reprocessable elastomers is crucial for the advancement of environmentally friendly wearable electronics. Herein, self-healing, degradable, and reprocessable polyimine elastomers with a cross-linked network constructed by dynamic imine bonds were synthesized under room temperature for a flexible strain sensor. Owing to the formation of a microphase separation structure by polyetheramine as soft segments and adipic acid dihydrazide as hard segments, the obtained polyimine elastomer exhibited superior mechanical properties with elongation at break of 1158% and tensile strength of 2.51 MPa. Moreover, the cross-linked network of dynamic imine bonds endowed the elastomer with outstanding self-healing capability and reprocessability. The healing efficiency reached 96.0% after healing at room temperature for 24 h, and the reprocessed elastomer maintained 80.6% of the original tensile strength after three reprocessing cycles. In addition, the polyimine elastomer was able to completely degrade into monomers under acidic condition within 180 min. The polyimine elastomer-based flexible strain sensor with liquid metal as conductive material processed excellent recovery ability of sensing performance even after being cut into two halves. The findings in this work conceivably stand out as a new methodology for the preparation of functional and environmentally friendly elastomers and flexible electronics.