CO₂-Derived Degradable Polythioester Adhesives From Proton-Trap-Assisted S/O Isomerization-Driven Cationic...

The development of degradable pressure-sensitive adhesives (PSAs) holds great promise for enabling the recycling of adhesive-containing materials. However, existing degradable PSAs are often constrained by insufficient or moderate adhesion strength, reliance on fossil-based feedstocks, and/or incomplete degradation. Addressing these challenges requires the development of new polymerization strategies and material designs. Herein, we report a proton-trap-assisted S/O isomerization-driven cationic ring-opening polymerization of the CO₂-derived thionolactone 3,6-diethyltetrahydro-2H-pyran-2-thione, which enables the well-controlled synthesis of high-molecular-weight CO₂-based (co)polythioesters. The resulting materials exhibit a unique combination of high and tunable peel strength (up to 16.43 N/cm), excellent optical clarity (over 96% transmittance, low haze and low yellowness index), and the ability to undergo either complete degradation or quantitative depolymerization under mild conditions, delivering the first practical example of polythioester-based PSAs. This study establishes a sustainable platform for PSA design that integrates robust performance with full life-cycle management, thereby advancing the utilization of CO₂-derived materials and circular polymer design.