Recent advances in entropy-driven ring-opening polymerizations

Entropy-driven ring-opening polymerization (ED-ROP) of unstrained macrocyclic monomers and/or oligomers employs the ring-chain equilibria between macrocycles and their corresponding polymers and the associated increase of conformational freedom to achieve high molecular weight materials. The principles of building macrocyclic compounds, their use in ED-ROP, and the practical considerations of polymerizations are described, and recent progress in this area is discussed through selected examples. The various polymerization techniques used for ED-ROP are discussed, including anionic, radical, coordination/insertion, ring-opening metathesis, and enzymatic polymerization methods. Emphasis is placed on the potential of ED-ROP in the synthesis of biomaterials and the development of enzyme-catalyzed green systems.