(760a) Self-Assembly of an Electronically Conductive Network Via a Microporous Scaffold

The Canadian oil sands contain an estimated 167 billion barrels of recoverable bitumen, but the recovery processes are both environmentally and economically expensive. An alternative scheme is to convert the energy in the bitumen hydrocarbon bonds to electrical energy in situ. One of the associated challenges with this novel idea is how to transfer the electrons generated at the site of bitumen oxidation over a distance to a collection site. Here we seek to transfer electrons through a network of nanowires spanning the distance between the reaction and collection sites. 

A goal of this work is to therefore design a model scaffold with tunable pore size and length to simulate a porous formation in which nanoparticles (NPs) can be dispersed. Paraffin microbeads of varying sizes (125 to 350 µm) were fused together serving as a hydrophobic scaffold, and Ir NPs were transported into the scaffold via a water/ethanol phase. The Ir NPs tended to self-assemble into conductive nanowires at the hydrophobic/hydrophilic interface of the paraffin and water. Electrochemical oxidation of the Ir to Ir oxide (IrOx) ensured good interconnectivity and rapid electron transfer kinetics through the IrOx NW network. Conducting atomic force microscopy was used to map the routes of electron transfer through the porous scaffold while scanning electron microscopy and confocal microscopy were used to image the NP/scaffold morphology. As a proof of concept, glucose oxidation over ca. 1 cm was detected from the site of oxidation by potentiometry. These early discoveries indicate that electronically conductive networks can be fabricated in a formation-like scaffold that allow electron transfer over extended distances.