From dynamic molecular bridging to achieving Healable, recyclable, photo/magnetic-responsive shape memory EVA@Fe3O4 hybrid network

Abstract

Dynamic networks show great potential in shape memory polymers (SMPs) not only because they can display excellent shape memory effects (SMEs), but also possess good recyclability and reprocessability due to their dynamic features. Additionally, multiple responsiveness is also an attractive characteristic for SMPs to meet diverse applications. while incorporating functional fillers into SMPs has been explored as a feasible solution, their performance relies heavily on the interface interactions. In this study, we present a facile strategy to construct a dynamic hybrid network that combines excellent multi-responsive SMEs and recyclability. This is achieved by using dihydroxyphenylpropionic acid (CA) to bridge EVA chains and multi-responsive Fe3O4 particles through transesterification and metal-ligand coordination. The hybrid networks exhibited favorable dynamic characteristics. Specifically, EVA-CA@Fe3O410% demonstrates remarkable thermal and light healing efficiency, exhibiting a mechanical strength recovery (ησ) of 102% and elongation at break recovery (ηε) of 95% after healing at 140 °C for 2 h, and a ησ of 107% and ηε of 92% when healing under near-infrared light (NIR) irradiation for 2 min, respectively. Furthermore, good recyclability was demonstrated by maintaining mechanical performance after three reprocessing cycles. Moreover, the hybrid networks exhibited excellent SMEs, enabling multifunctional deformation triggered by heat, NIR and alternating magnetic fields.