Entropically driven ring-opening-metathesis polymerization of macrocyclic olefins with 21-84 ring atoms

Giant rings make neat monomers: Macrocyclic olefins with up to 84, and possibly even more, ring atoms undergo ring-opening-metathesis polymerization (ROMP) to give high-molecular-weight polymers when the monomer is used neat or at very high concentration (see scheme). This type of ROMP is driven by entropy changes, unlike standard ROMP, which is carried out using strained cyclic monomers and is driven by the enthalpy change of the reaction