Closed-loop chemically recyclable photo-responsive dynamic polymers with tunable properties and multi-funcionality

In the pursuit of sustainable polymers, there is a growing interest in closed-loop chemical recycling to monomer (CRM), a process that allows post-consumer polymers to revert to their original monomers. Cyclopentene (CP) and its derivatives are representative molecules that exemplify an efficient CRM process under mild conditions. However, most CP-based polymers possess limited thermal and mechanical properties, constraining their potential applications. Here, we propose new CP-based poymers with autonomous and tunable functions by integrating anthracene as a dynamic functional motif. Anthracenes not only serve as supramolecular cross-linkages through strong π-π interactions but also form stronger chemical ones under UVA light irradiation, inducing remarkable changes of polymer properties. Furthermore, damage-detecting, self-healing, and local shape reprogramming capabilities are accomplished by utiliziing the reversible nature of photo-dimerized anthracene. A mild and selective depolymerization condition for our polymers facilitates efficient monomer recovery even from mixed plastic wastes. This work presents a simple yet effective strategy to expand the scope of sustainable polymer society by combining two orthogonal reversible chemistries.