A fast self-healing and mechanical-enhanced polyurethane via Cu-pyridine coordination

The ability to repair rapidly is extremely important for self-healing elastomers in practical applications. Here, we fabricate a fast self-healing polyurethane with enhanced mechanical properties by introducing Cu-pyridine coordination in the hard segments. The cupric ions coordinate with the pyridine groups, effectively increasing the hydrogen bonds between urea bonds. With the incremental coordination bonds and hydrogen bonds in hard segments, the mechanical properties of the polyurethane are improved while the soft segments still keep the good mobility. Combined with the strong photothermal effect of Cu-pyridine coordination, the healing speed of the elastomer is promoted greatly. As a result, the elastomer owns good tensile strength up to 5 MPa and fast self-healing properties (healing efficiency up to 53% in 30 s and 99% in 2 min after irradiation with a 785 nm laser).