APPLICATIONS OF POLYAMIDOAMINE DENDRIMERS IN POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

ii Dendrimers are highly branched macromolecules with well-ordered three-dimensional architectures. Polyamidoamine (PAMAM), the most common class of dendrimers, have been widely studied due primarily to the following three features: 1) the interior amine and amide groups that can interact with ionic metal precursors through ligand exchange reactions; 2) the presence of an interior void space in the higher generation dendrimers; and 3) the exterior primary amine groups that permit further functionaliztion. These unique structural features have inspired many potential applications. This dissertation describes two applications of PAMAM dendrimers in polymer electrolyte membrane fuel cells (PEMFCs). First, in an effort to improve the utility of Pt in PEMFCs, PAMAM G4 was used as both a template and a stabilizer to synthesize dendrimer encapsulated Pt nanoparticles (Pt DENs) by photoreduction. These nanoparticles are highly monodisperse, exhibit high specific activity for the oxygen reduction reaction, and are inert to methano