Evaporation-Assisted Synthesis of Olympic Gels

Catenated networks exclusively composed of intertwining rings were first envisioned as "Olympic gels" by Pierre-Gilles de Gennes four decades ago but have not been successfully prepared in artificial materials yet due to the challenge in synthesis. Herein, we present a bio-inspired, evaporation-assisted strategy to address this issue. In our design, the evaporation of liquid catalysts that induce ring-chain equilibrium of polymer systems drives macrocycles to encounter and assists their catenation through reversible cyclization. Complete removal of liquid catalysts stabilizes the resulting ring-interlocked networks by deactivating the catenation-decatenation process. The strategy is demonstrated by the system of hydroxyethyl lipoate (LpHE) and dimethyl formamide (DMF). The results indicate that DMF evaporation leads to the formation of global LpHE polycatenane networks. This evaporation-assisted strategy displays versatility in several tested cyclic monomers, highlighting its potential as a general approach to fabricate ring-interlocked elastomers and topologically intricate materials.