Stabilizing and controlling the spatial arrangement of metallic nanoparticles with polymers has been of great research interest. Multi-block copolymers can phase separate at nanometer scale to adopt a series of morphologies from spherical to cylindrical to gyroid to lamellar. Incorporation of appropriate functional groups within specific blocks of block copolymers can enable the localization of metallic species to specific nanometer-scale domains. We have synthesized alkyne functional polystyrene-block-poly(4-(phenylethynyl)styrene) (PS-b-PPES) diblock copolymers and poly[4-(phenylethynyl)styrene]-block-polyethylene oxide-block-poly[4-(phenylethynyl)styrene] (PPES-b-PEO-b-PPES) A-B-A triblock copolymers over a range of molecular weights and compositions by reversible addition-fragmentation chain transfer (RAFT) polymerization. Reaction of dicobalt octacarbonyl with these block copolymers proceeded with selective incorporation of cobalt species (Co2(CO)6) to the alkyne-functionalized blocks. The phase behavior of these block copolymer-cobalt adducts was studied by transmission electron microscopy (TEM). The observed morphologies of the cobalt-containing copolymers shift from PPES/Co minority domains to PPES/Co majority domains as the weight fraction of the PPES/Co blocks increases. Heating these composites leads to loss of CO groups and formation of cobalt nanomaterials. Both PS-b-PPES and PPES-b-PEO-b-PPES cobalt nanocomposites exhibited magnetism after thermolysis. This study provides a method to localize metallic species in an organic matrix at nanometer scale, in which the morphology and size of the metal-containing regions is tunable by altering the polymer composition. Such an approach shows potential in nanopatterning, catalyst preparation, and many other areas.

Synthesis and phase behavior of alkyne-functionalized di- and triblock copolymers and their cobalt carbonyl adducts

249th National Meeting (2015)

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