The critical role of inter-component hydrogen bonds in the formation of reversibly interlocked polymer networks

Abstract

Recently developed reversibly interlocked polymer networks are made from two pre-formed crosslinked polymers containing reversible covalent bonds via topological rearrangement. Unlike interpenetrating polymer networks, the resultant is rather homogeneous regardless of the miscibility between the parent single networks, and can be repeatedly self-healed and unlocked/re-locked. The present work focuses on revealing the critical role of the hydrogen bonds between the single networks in the construction of the interlocked networks, cooperating with dissociation and re-association of the built-in reversible covalent bonds. Based on the systematic investigations of the small molecules, single networks and interlocked networks, the inter-component hydrogen bonds of the interlocked networks are found to be able to be built-up, which are more stable than the intra-molecular hydrogen bonds of the single networks. They help to pull the chains from different single networks together, preventing the occurrence of phase separation during interlocking and implementing the valuable forced miscibility. Besides, abundant but weak inter-component hydrogen bonds are preferred. The outcomes not only show the hitherto unknown part of the mechanism involved in the formation of the interlocked networks, but also benefit the design of new members of interlocked networks.