Sustainable Self-Healing Electrospun Fibers Enabled by Upcycled TPEE/PCL Blends through Dynamic Chain Mobility

Upcycling polymer waste into functional fibrous materials is attractive for sustainable materials development, but a fundamental challenge remains: electrospun fibrous structures are highly susceptible to damage, while healing processes based on chain diffusion often induce structural collapse, loss of interfiber connectivity, and deterioration of mechanical performance. Here, we address this issue by developing an upcycled thermoplastic polyester elastomer (TPEE)/polycaprolactone (PCL) electrospun fibrous system that balances structural integrity with dynamic healing capability. In this design, the mechanically supportive TPEE framework helps retain fibrous features in selected blend compositions, while the semicrystalline PCL phase provides thermally responsive domains that promote segmental motion and interfacial chain diffusion under mild heating. This cooperative structure enables effective intrinsic self-healing without external healing agents or complex chemical modification while minimizing collapse of the fibrous network during repair. The results reveal a composition-dependent interplay between healing efficiency and mechanical robustness, demonstrating that controlled integration of a supportive elastic matrix with a reversible thermally active phase provides an effective strategy for extending the functional lifetime of upcycled fibrous materials.