Dripping-onto-substrate extensional rheometry of the ultralong supramolecular polymer solutions

Supramolecular polymers which are utilized for viscosity modification, mist control, and drag reduction can give striking changes to the flow behavior of materials with their extremely high molecular weight and extraordinary chain extensibility. There have been several approaches to form supramolecular polymers such as assembly of associative polymers, however, the synthesis of ultralong polymers was only available to a limited extent. Accordingly, despite the importance of understanding not only shear rheological properties but also the dynamic response of ultralong supramolecular polymers under elongational flow, there have been few studies on them. In this research, ultralong supramolecular polymers were produced through a coordination complex between metal ions and ligands at both ends of linear building blocks. The size of the unit building block, the coordination number of metal ions, and pH conditions were manipulated to optimize the length of the supramolecular polymers. Finally, the extensional rheology and pinching dynamics of ultralong polymer solutions were analyzed using dripping-onto-substrate rheometry, and the relationship between the strength of the coordination bond and the chain extensibility has been investigated.