Applications and Extensions of Living Ring-Opening Metathesis Polymerization

Living ring-opening metathesis polymerization (ROMP) is a polymerization method that has recently become popular in the synthesis of complex polymers due to advances in olefin metathesis catalyst design. The unrivaled degree of functional group tolerance of the method, coupled with a high level of control and synthetic ease, make living ROMP a valuable tool in the assembly of complex nanostructures and functional polymers. Work in this thesis details methods for applying living ROMP in the assembly of complex nanostructures and extending the uses of living ROMP to end-functionalized polymers and to polymers synthesized in a catalyst economical manner.;Chapter 2 describes the synthesis and radiofluorination of fluorine-18 functionalized nanoparticles assembled from polynorbornene block copolymers synthesized via living ROMP. The block copolymers include a hydrophobic photo-crosslinkable block made from a novel cinnamate-containing norbornene, as well as a hydrophilic block made from a PEGylated norbornene. Chapter 3 illustrates another application of ROMP-based nanoparticles in which polynorbornene block copolymers are assembled into Janus (hemispherical) nanoparticles.;A method for end-capping ROMP polymers using a symmetrical alpha-bromoester-containing cis-olefin terminating agent is described in Chapter 4. Subsequent atom transfer radical polymerization (ATRP) from the functionalized chain end confirms complete end-functionalization and was used to synthesize mechanistically incompatible block copolymers. Chapter 5 extends this polymer end-functionalization approach to additional functional groups, including alcohols, bromides, thioacetates, fluorescent compounds, biotin, and others.;A thorough study of pulsed-addition ROMP (PA-ROMP) performed using a Symyx robotic system is presented in Chapter 6. Extending the end-capping methodology described in Chapters 4 and 5 to the synthesis of additional polymer chains led to a homo- and block copolymerization strategy that can produce more than one polymer chain per molecule of metal initiatior. The PA-ROMP strategy reduces catalyst consumption as much as sevenfold in the synthesis of polynorbornenes.;Appendix 1 describes the synthesis and ROMP of several norbornene monomers, including a copper-64 chelating norbornene, that were not addressed in the previous chapters but that may be useful for future studies on functional ROMP polymers and nanostructures. Appendix 2 contains additional mathematical details on PA-ROMP.