Concatenated ring network arising from occasional branching of long linear concatenated ring strings

Classical theories predict that network formation from difunctional polymers is impossible due to the absence of ring formation and intramolecular reactions. Herein, we demonstrate that silicone elastomers can be synthesized via a platinum-catalyzed hydrosilylation reaction between divinyl- and dihydride-telechelic poly(dimethylsiloxane) (PDMS) across a wide range of stoichiometries. These elastomers exhibit elongations exceeding 2500% and Young’s moduli as low as 50–250 kPa, well below the entanglement threshold of PDMS (~600 kPa). Sol fraction analysis reveals that many polymers remain unincorporated into the network and possess exceptionally high molecular weights (~100-400 kg/mol). Chemical and rheological studies, complemented by molecular simulations, support a new network architecture termed a concatenated ring polymer network, composed of long chains of interlinked rings that contain irregular branching and crosslinking points. This architecture explains the unusual softness and extensibility of the materials, challenges conventional assumptions about network formation, and provides a framework for designing ultra-soft, highly extensible elastomers based on controlled ring architectures. Classical theories predict that difunctional polymers cannot form networks due to the absence of ring formation and intramolecular reactions. Here, the authors demonstrate that silicone elastomers formed via PDMS hydrosilylation yield ultra-soft, highly extensible materials with interlinked ring-chain networks.