Untying the Knot: A Fully Recyclable, Solvent-Free, Wide-Spectral Photocurable Thermoset Adhesive

Adhesives are vital in industries ranging from aerospace to consumer electronics. However, their reliance on non-recyclable polymers makes them suitable for one-time use and results in significant economic and environmental challenges. Reversible adhesives, based on covalent adaptable networks, address these issues and open possibilities for applications, including recyclable multi-layer packaging, removable labels, and fully recyclable electronics - batteries, smartphones, etc. Despite progress in dynamic and reversible bonds, current solutions often compromise performance or the ability to detach from substrates. This study proposes reversible high-performance adhesives that can undergo cycles of bonding-debonding without commonly reported need to add solvent, high-temperature processing or use deep-UV irradiation while maintaining adhesives' functionality and reducing environmental impact. The bonding is done by rapid photocuring, which occurs within 30 seconds under irradiation at a wide range of visible wavelengths (400-650 nm) while achieving constant adhesion strength across diverse substrates, including underwater adhesion. De-bonding is achieved using a simple household microwave. Furthermore, the adhesive's transparency and high refractive index enable its use in various optical applications, whereas its robustness in wet conditions expands its potential for bioadaptive or underwater systems. This adhesive represents a significant step toward sustainable adhesives that seamlessly integrate high performance with circular-economy principles.