A high strength, high toughness and transparent room-temperature self-healing elastomer based on the synergy effect of quadruple dynamic bonding structure

As a functional material, the transparent elastomers have been rapidly developed and applied in different fields, such as electroluminescence devices, sensors, medical and communication equipment. However, it is a huge challenge to prepare the transparent elastomers with excellent room-temperature self-healing performance and high mechanical performance. Herein, based on the synergy effect of quadruple dynamic reversible interaction, we proposed a new strategy to synthesize a room-temperature self-healing polyurethane elastomer with high strength of 15.3 MPa, high elongation at break of 1232% and high transparency. First, the polyurethane elastomer exhibited high elongation and toughness based on mechanical energy consumption from reversible fracture and reformation of sacrifice bonds, including hydrogen bonds and coordinate bonds. Moreover, the rapid reversible reaction of boronic ester bonds, oxime bonds and especially hydrogen bonds endowed the elastomer excellent self-healing performance. After introducing coordinate bonds, the elastomer exhibited high strength based on increased hard segment microdomains and the microphase separation. To further probe the mechanisms of room-temperature self-healing process and high mechanical performance, the molecular chain mobility was studied. The relationship among molecular chain mobility, molecule chain entanglement, microphase separation and aggregation structure were revealed, indicating molecular chain mobility was the key factor to self-healing performance in polyurethane elastomer.