Reprocessable, Self-Healing, Thermadapt Shape Memory Polycaprolactone via Robust Ester-Ester Interchanges Toward Kirigami-Tailored 4D Medical Devices

Integrating desirable multifunctionalities that are completely independent of each other into one classical polymer network without complex chemical synthesis and modification is a great challenge. Here, we report a self-healing, reprocessable, and thermadapt polycaprolactone (PCL)-based shape memory poly-mer with robust ester-ester interchange catalyzed by dibutyltin dilaurate (DBTDL). The polymer system is fabricated by the common free-radical polymerization of PCL diacrylate. This approach is straightforward and has outstanding reproducibility. It has been revealed that DBTDL was a stable, efficient, oxidation-resistant, and nonstaining catalyst system for the ester-ester interchange. Intriguingly, there was a real critical exchange reaction temperature in the dynamic exchange system. Once over 90 degrees C, the dynamic reaction was quickly activated, while below 90 degrees C, the dynamic reaction was completely dormant, in stark contrast to the typical triazabicyclodecene (TBD)-catalyzed transesterification. Based on the versatile ester-ester dynamic exchanges, an unprecedented shape memory PCL with a combination of self-healing, reconfigurability, and reprocessability was achieved, any of which demonstrates its special prowess. Kirigami-tailored medical devices with 4D shape transformation, such as a pyramidal scaffold and reticulate vascular stent, were successfully created through the synergistic use of kirigami and reconfigurability. The biodegradable PCL-based thermadapt shape memory polymer with a combination of self-healing, reconfigurability, and reprocessability is expected to significantly expand the possible applications of smart biomedical devices with complex topological geometries.