Evaluation of shape memory and self-healing of poly(ε-caprolactone)/poly(ethylene-co-methacrylic acid) ionomer (PCL/EMAA-Zn) blends

This study explores the viscoelastic, self-healing, and shape memory properties of poly(ε-caprolactone) (PCL), the ionomer EMAA-Zn, and their blends in different proportions (70/30, 50/50, 30/70) using torque rheometry, rheological analysis, FTIR spectroscopy, X-ray Diffraction, Dynamic Mechanical Analysis (DMA), scanning electron microscopy (SEM), and shape memory evaluations. The objective is to investigate the synergistic effects of ionic bonds, clusters, and PCL diffusion in PCL/EMAA-Zn blends for potential applications requiring thermo-responsive shape memory and self-healing capabilities. Rheological analysis identifies distinctive viscoelastic properties, with PCL/EMAA-Zn (30/70) exhibiting commendable scratch healing capabilities and relatively strong mechanical properties. FTIR spectra confirm characteristic absorption bands, while DMA highlights transitions corresponding to PCL melting and order–disorder shifts in EMAA-Zn clusters. XRD patterns demonstrate the persistence of crystalline structures in blends. SEM images reveal morphological differences, with the (50/50) blend displaying a co-continuous structure. Shape memory evaluations showcase promising results in both water immersion and torsion mode, emphasizing the potential for PCL/EMAA-Zn blends in shape recovery applications. Furthermore, self-healing analyses indicate superior performance in the blends, particularly (50/50) and (30/70) compositions, showcasing healing efficiencies of 90% and 96%, respectively. In conclusion, the study positions PCL/EMAA-Zn blends as promising materials for applications requiring thermo-responsive shape memory and efficient self-healing, showcasing the intricate interplay of ionic interactions, supramolecular bonds, and PCL diffusion in achieving optimal properties. Graphical Abstract