Functional polyolefins containing disulfide and phosphoester groups: Synthesis and orthogonal degradation

Disulfide-containing polyolefins were prepared by ring-opening metathesis polymerization (ROMP) of disulfide containing cyclic olefin 1, (Z)-3,4,7,8-tetrahydro-1,2-dithiocine, with other cyclic olefins. This allowed the generation of new degradable polyolefins with nearly 30 mol % disulfide monomer in the backbone, along with functional cyclooctene comonomers bearing pendent hydroxyl, amino, and pentafluorophenyl ester groups. Integration of disulfide groups into the polymer provides redox responsiveness as well as mechanisms for polymer degradation through added reducing agents, thiols for degradative equilibrium exchange, or UV irradiation. This ROMP copolymerization strategy was extended to terpolymers containing both disulfides and phosphoesters that exhibit orthogonal degradation properties.