Multifunctional Roles of Iron Oxide Nanoparticles in a Reversible Shape‐Memory Composite

Abstract The utilization of functional fillers in the development of composite materials has come a long way since its advent to improve physical, chemical, or mechanical properties of the base material. However, the heterogenous roles contributed by a single type of filler remain uncommon in this field. Here the endowment of various modifications to a 1,8‐octanediol/1,12‐dodecanedioic acid/citric acid (OD/DDA/CA) matrix through the incorporation of iron oxide nanoparticles (IONPs) is reported. Owing to the relaxation and hysteresis loss behaviors of IONPs when exposed to an alternating magnetic field (AMF), the composites demonstrate a magnetothermal response. Similarly, the excitation and relaxation of electrons in IONPs under near‐infrared light (NIR) enable photothermic‐responsiveness. In combination, two findings nurtured an observed shape‐memory effect when the samples are under actuation by these indirect stimuli, where a shape recovery ratio (≥98%) and reversible strain (≤7%) are recorded. Moreover, the catalytic role of IONPs aided transesterification in the covalent network, demonstrated by successful repeated cycles of shape reconfiguration of the samples. This work highlights the prospectives of multifunctional composite fillers in the exploration of bio‐derived composite smart materials.