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

Abstract

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 polymer 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 °C, the dynamic reaction was quickly activated, while below 90 °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.