Facile Preparation of a Poly[2]Catenane Network Using Self-Assembled [2]Catenane Unit.

Polycatenanes are an emerging class of polymeric materials linked through interlocked rings, possessing a higher degree of conformational freedom and mobility. However, the number of its studies is far lower than that of other dynamic polymers. This may reflect the fact that the preparation of polycatenanes involves the complicated synthesis of a covalent catenation (ring closing) step. Here we report a self-assembly approach that allows the facile preparation of a poly[2]catenane network with good material properties. First, a clip-type self-associated dimer is generated through a spontaneous self-assembly process driven by hydrogen bonding interactions between two individual isophthaloyl bis(diamine) subunits modified with olefin groups. Next, polymerization via a thiol-alkene click reaction is used to produce an H-bond-based polymer network. Finally, ring closure involving the formation of dynamic imine bonds was used to create a series of poly[2]catenane-containing networks. The resulting polymer networks not only demonstrated excellent mechanical features and stimuli-responsiveness but also proved ready degradability. We believe that this work will significantly accelerate the development of polycatenane materials.