Synthesis and Characterization of Shape Memory Poly (ε-caprolactone) networks with Programmable and Reconfigurable Shape-Morphing Behaviors

Abstract

Abstract Poly(ε-caprolactone) (PCL)-based semi-crystalline polymer are shape memory materials that has been extensively used in the biomedical field. Despite the large number of studies aimed at constructing the well-defined crosslinked polymer networks, detailed investigations of properties in terms of structural factors at the molecular level that influence the thermal-mechanical and shape memory properties are still poorly understand and investigated. In this work, PCL crosslinked networks with different molecular weight of diacrylate PCL prepolymers (Mn) are prepared via base-catalyzed Michael addition. The results indicate that the overall melting temperature, the crystallization temperature and the crystallinity of the networks exhibit an upward trend with increment of Mn. Besides that, the tensile strength and shape memory performance are also correlated with Mn. Controlled-strain DMA characterization on shape memory properties show that the cPCL-10000 network exhibits the most remarkable shape fixity and shape recovery ratio, indicative of lowering cross-linking density and chains mobility. In particular, editable shape memory properties can also be achieved by triggering transesterification within the same polymer network, and a possible molecular mechanism responsible for the elasticity-based shape memory effect and plasticity-based permanent shape reconfigurability is proposed and combined to present the shape-morphing behaviors.