Magneto-Responsive Nanocomposites with a Metal–Ligand Supramolecular Matrix

Magneto-responsive nanocomposites are prepared by mixing 1-5 vol % of Fe nanoparticles (NPs) in a metallo-supramolecular network made of poly(n-butyl acrylate) (PnBA) bearing terpyridine side groups and cross-linked by the addition of different amounts of Zn2+ ions. To have a clear understanding of the stepwise increase of complexity, the thermomechanical behavior of these materials was characterized through shear linear rheology at each step of their preparation. The metallo-supramolecular networks reveal a clear transition from polymer- to network-driven dynamics when passing progressively from low (<0 degrees C) to high temperature. While terpyridine (TPy)-Zn2+ complexes are usually treated as independent "stickers", the analysis of our master curves strongly suggests their aggregation. After the addition of 1-5 vol % of Fe nanoparticles within the supramolecular networks, we evidence the presence of TPy-NP bonds, resulting in a hybrid network of much longer relaxation time. Lastly, we combine thermal imaging and induction heating to emphasize the signature of sticker dissociation, offering new technical solutions to deepen our fundamental understanding of supramolecular networks.