Multiresponsive, Self-Healing, and Hierarchical Materials Constructed from Anion Recognition-Based Supramolecular Polymer Networks

Abstract

3A type supramolecular monomers in which three calix[4]pyrrole units connected to a central benzene unit with varying linker lengths were synthesized through azide-alkyne click reactions between two different azide cores and an alkyne-functionalized calix[4]pyrrole. These compounds were then complexed with a BB-type monomer tetrabutylammonium suberate in chloroform and acetonitrile via hydrogen bonding between calix[4]pyrrole units of 3A monomers and carboxylate units of suberate anions, leading to the formation of anion recognition-based supramolecular polymer networks. Owing to the dynamic noncovalent interactions, the resulting systems were found to be responsive against temperature, competing anions, and pH. Rheological analyses of the supramolecular polymer networks revealed that the system with a longer distance between the benzene core and calix[4]pyrrole units exhibits transient network behavior and viscoelastic self-healing ability below 20% deformation ratio. These systems were also used for the fabrication of hierarchical materials ranging from zero-dimensional (0D) to three-dimensional (3D) by utilizing various methods. This work demonstrates for the first time the preparation of anion recognition-based supramolecular polymer networks based on calix[4]pyrroles and their utilization in the formation of multiresponsive, self-healing materials for the fabrication of hierarchical materials.