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, oxidationresistant, 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.

Mechanically robust shape‐morphing materials that can transform from miniaturization into complex structures are highly desirable for real‐world device applications. However, fabricating mechanically robust yet geometrically complex 3D shape‐morphing structures with excellent functionality and high load‐bearing capacity remains a challenge. Inspired by drum tower buildings, a simple, rapid, and universal method is presented for fabricating multifunctional shape‐memory smart devices with complex and rigid 3D kirigami geometry in the two‐stage epoxy‐amine‐acrylate photopolymer systems. In the first‐stage reaction, transparent polymer films with a Tg of 29–49 °C are obtained by the epoxy‐amine chemistry. The shape‐memory programming process allows the first‐stage film with a drum tower‐inspired 2D kirigami pattern to be manipulated into an unsupported 3D structure. In the second‐stage reaction, UV‐induced free‐radical polymerization of methacrylate groups in the first‐stage network is employed to rapidly lock the programmed 3D kirigami structure with a Tg of 66–138 °C. The drum tower‐inspired 3D kirigami structure withstands 1000 times its own weight. The shape memory fluorescent 3D device and shape memory electronic 3D device are engineered by combining the two‐stage photopolymer system and a 3D kirigami structure. This work represents a versatile method to create multifunctional shape‐memory devices with rigid 3D geometry for potential applications.

The impact of branching architecture of one continuous uncrosslinked phase on properties of classic shape memory semi‐interpenetrating polymer networks (semi‐IPNs) was explored. Crosslinked poly (methyl methacrylate) (PMMA)/star‐shaped polyethylene glycol (PEG) (PMMA/SPEG) semi‐IPNs and PMMA/linear PEG (PMMA/LPEG) semi‐IPNs were synthesized with the same PEG content. Mechanical properties, phase structure, thermal properties, dynamic mechanical properties, and shape memory properties of these two semi‐IPNs systems were compared. Due to the better compatibility of SPEG in the PMMA network, which was derived from little crystallization compared with PMMA/LPEG semi‐IPNs, PMMA/SPEG semi‐IPNs exhibited a combination of large tensile strength and high elongation at break. PMMA/SPEG semi‐IPNs, which had little crystallization exhibited superior shape recovery versus PMMA/LPEG semi‐IPNs, which had more crystallization. Moreover, the higher the crystallinity in PMMA/PEG semi‐IPNs was the worse long‐term temporary shape retention. Based on tube model theory, the high shape recovery capacity of PMMA/SPEG semi‐IPNs is mainly ascribed to the retraction of free PEG arms, which is entropically favorable and thermally activated due to the fluctuations of the path length. This result is supported by stress relaxation analysis and the influence of long shape fixity time on shape fixity ratio for these two systems.