Biomimetic supramolecular polyurethane with sliding polyrotaxane and disulfide bonds for strain sensors with wide sensing range and self-healing capability.

To prolong the service life of flexible electronic materials, polymeric matrixes with excellent self-healing capability and integrated mechanical properties are highly desirable, but the balance between the self-healing capability and mechanical properties is a grand challenge. Here, polyrotaxanes as sliding crosslinkers and dynamic disulfide bonds are incorporated into the main chains of polyurethane (PU) via one-pot synthesis, which endows the PU with polydisperse hard/soft segments, high density of self-healing points and energy dissipation. Based on this judicious molecular design, the PU elastomers exhibit exceptional mechanical properties, such as high stretchability (1167 % with a tensile strength of 3.49 MPa), high fracture energy (20,775 J m-2) and high puncture energy (200.70 mJ). Moreover, due to the presence of dynamic reversible hydrogen and disulfide bonds, the elastomer could achieve stress and strain repair efficiencies of 93.98 % and 99.21 % at 100 ℃ within 1 h, respectively. The above-mentioned superiorities enable the bioinspired strain sensors to possess a large sensing range (∼596 %), high sensitivity (∼79.98), short response time (∼128 ms), along with excellent reliability and self-healing ability. Besides, the strain sensor exhibits remarkable recyclability and prominent reprocessability, which nicely solves the pollution by discarded electronics.