(63ab) Proton Conducting Polymer Films within Nanoporous Gold Leaf Electrodes

A novel approach to the design of a fuel cell cathode that contains a minimal amount of platinum incorporates an ionomer-filled nanoporous gold leaf coated with a platinum monolayer. Because of pore size-related limitations and the delicacy of gold leaf, a traditional ionomer substance such as Nafion cannot be simply applied to the surface. Instead, to achieve conformal coating throughout the pores, the ionomer film must be polymerized on-site using surface initiated ring-opening metathesis polymerization of norbornene monomer equipped with a fluorocarbon side chain. The conditions for this reaction must be finely tuned to ensure that monomer has access to all surfaces of the gold, that there is a sufficient amount of monomer to achieve conformal coating, and that the monomer is not in such an excess that would lead to excessive overgrowth or pore plugging. The goal of this research was to determine both the appropriate variables and the optimal reaction conditions for the desired coating. It was found that the two main factors that affect polymerization quality are the gold pore size and the monomer solution concentration. Working ranges in each of these variables were established.