Ultrastable, supertough and photohealable polymer

There is usually a mutual trade-off between thermodynamic stability, kinetic activity and external field responsiveness in polymer chemistry. Here, we report a Cu(II)-coordinated benzoquinone dioxime-carbamate unit (Cu-BQDU) that resolves this challenge in polymers. Through an inductive effect, coordination bonds polarize hydrogen bonds, enhancing their strength to the highest reported value for carbamate-carbamate segments in hydrogen bonding (∼5.6 kcal/mol). The resulting polymer exhibits exceptional thermodynamic stability and achieves a record-high toughness of 236.0 MJ/m³ among intrinsic photothermal elastomers. Additionally, the coordination bond extends the molecular conjugation length, optimizing the geometric alignment of π-π interactions to enhance photothermal conversion efficiency. This effect synergizes with Cu(II)-catalysed carbamate dynamics, boosting near-infrared-light-driven photothermal healing efficiency by 92.9%. This work provides multiple new molecular design principles of polymers.