Acquiring a versatile polyurethane (PU) elastomer with both high mechanical properties and rapid low-temperature healing for flexible nanosensors represents a significant challenge. Inspired by the synergistic effects of dynamic bonds, we introduce the dynamic sextuple hydrogen bonds (H-bonds) from adipic dihydrazide (AD) and flexible dynamic disulfide bonds (S–S bonds) from the chain extender 3,3′-dithiobis(2-butanol) (DS) into PU main chains to fabricate a high-performance elastomer (PU-3) with remarkable mechanical robustness and rapid self-healing capability. Specifically, AD imparts PU-3 with an exceptional tensile strength of 40.5 MPa and a toughness of 287.8 MJ m–3. A 1.1 g sample (50 mm × 10 mm × 1.3 mm) supports loads up to 11,000 times its own weight. In addition, the excellent DS unit, featuring four branched methyl groups with a substantially larger molecular volume, renders the PU-3 more flexible with an outstanding elongation at break of 1445.2%. Moreover, PU-3 exhibits excellent resilience, self-healing efficiency, and recyclability. As a result, a flexible polymer/carbon nanotube composite nanosensor is constructed from this elastomer matrix and multiwalled carboxylated carbon nanotubes (MWCNTs-COOH) as the conductive filler, exhibiting outstanding sensitivity and rapid response and recovery capabilities, thereby highlighting its potential for applications in health monitoring and intelligent wearable electronics.
Wei et al. (Tue,) studied this question.