# Ultrastable, supertough and photohealable polymer

## TL;DR

A new polymer is developed that is highly stable, tough, and can heal under light, thanks to copper-based molecular design.

## Contribution

The use of Cu(II)-coordinated units to simultaneously enhance hydrogen bonds, π–π interactions, and self-healing in polymers is novel.

## Key findings

- The polymer achieves a record toughness of 236.0 MJ/m³.
- Photothermal healing efficiency is boosted by 92.9% using Cu(II)-catalyzed dynamics.
- Hydrogen bond strength reaches ∼5.6 kcal/mol, the highest for carbamate–carbamate segments.

## Abstract

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.

Leveraging coordination bonds to simultaneously polarize H bonds, optimize π–π interactions and catalyse oxime–carbamate bonds achieves the simultaneous enhancement of elastomers’ mechanical properties, thermal stability, photothermal conversion efficiency and self-healing efficiency.