Thermo-responsive topological metamorphosis in covalent-and-supramolecular polymer architectures

Topological metamorphosis represents a powerful approach to modulate the properties of polymers.However,it still remains a major challenge to achieve the tunability of bulk mechanical properties via topological transformation in supramolecular polymer systems.Herein,we couple the covalent polymer and supramolecular polymer in a single system—referred to as covalent-and-supramolecular polymer(CSP)—to realize a thermo-responsive macromolecular metamorphosis.The CSP is able to topologically switch from grafted polymer to cross-linked network by taking advantage of synergistic dynamic covalent interactions and host–guest interactions.Benefiting from the topologically structural transformation,brittleness intrinsically evolves into toughness in our CSP architectures with minimum change of their molecular compositions from furan–maleimide to anthracene–maleimide linkers.Our work demonstrates that supramolecular polymers are a promising platform to design smart materials not only due to their inherent stimuli-responsive properties but also because of their abilities in determining bulk mechanical properties of polymers with alterable topological structures.