<u>Supramolecular Cross-linked Hydrogels: </u><u>Similarities and Differences with Chemically Cross-linked Networks </u>

Over the past decades, hydrogels have been widely studied due to their numerous applications especially in medical sciences. Depending on the application, the network of water-soluble polymer chains can be chemically or physically cross-linked by using permanent or transient bonds respectively. This diversity of cross-linking junctions offers a great versatility to synthesized hydrogels. In this scope, we developed a supramolecular cross-linker based on coordination chemistry that can be integrated in a stimuli-responsive gel through a one-pot synthesis. Supramolecular gels show great similarities with the structure of a chemically cross-linked network build with the same monomer but exhibit a different swelling behavior and an ability to undergo a gel-to-sol transition when an external stimulus is applied. This stimuli-responsiveness gives rise to the controlled tuning of the overall cross-link density and so of the network macroscopic properties. It also gives interesting insights on the accessible range of properties of dual gels that can be synthesized with both chemical and supramolecular cross-linkers.