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Multiscale Modeling of Polymeric Materials
Achievement/Results
IGERT Associate Qifei Wang successfully completed his Ph.D. in Chemical Engineering from the University of Tennessee Knoxville in August 2012. His Ph.D. work was exemplary of the STAIR IGERT because it concerned sustainable technology, specifically multiscale materials modeling of novel polymeric materials for use in proton-exchange membrane (PEM) based fuel cells. Widespread adoption of fuel cells is held back in part due to the expense of fuel cells, which in large part is based on the platinum catalyst in the electrode. If the fuel cell were operated at higher temperature, the catalyst would be more active and less susceptible to poisoning, so less platinum could be used and the cost of the entire fuel cell would drop. However, running the fuel cell at a higher temperature boils the water out of the PEM, making the fuel cell inactive. Thus, the technical challenge is to develop high-temperature fuel cells. Qifei’s work is helping lead researchers to a molecular-level understanding of the structural characteristics required of high temperature fuel cell PEMs.
Qifei Wang’s Ph.D. work is also exemplary of the STAIR IGERT because it was interdisciplinary work. Prof. Jimmy Mays and post-doctoral researcher Suxiang Deng in the Chemistry Department synthesized the novel PEM and characterized their conductivity. The modeling team of Qifei Wang and advisor, Dr. David Keffer, from Chemical & Biomolecular Engineering, worked closely with the experimental synthesis and characterization team to make sure the simulations corresponded as closely as possible to the experimental work.
During his work, Qifei developed a coarse-graining procedure based on integral equation theory to allow computational simulation of much longer polymer chains than is able using traditional molecular dynamics simulation. This paper caught the attention of Dr. Gary Grest at Sandia National Laboratory. In a side effort, Qifei published a paper applying his coarse-graining procedure to the simulation results for nanoparticles performed by Grest. This paper was published in J. Chem. Phys. and received the Journal of Chemical Physics Editor’s Choice Award for 2011.
Having graduated, Qifei is applying his skills as a post-doctoral researcher working with Dr. Orlando Rios at Oak Ridge National Laboratory using the same simulation techniques that he applied to fuel cells to study lithium ion transport in novel carbon electrodes made from renewable materials. Dr. Rios is an experimentalist and Qifei is providing the modeling work. It is clear that Qifei’s participation in the STAIR program has prepared him for a future in better understanding sustainable technology through collaborative experimental and modeling research.
Address Goals
A defining challenge of the future is the search for sustainable sources of energy and training the next generation of engineers who will lead the way in the discovery and implementation of these new energy sources. The search is a complicated task and requires interdisciplinary training and collaboration among different disciplines. Fuel cells are becoming an important part of the solution mosaic. Qifei’s work is helping to advance researchers’ knowledge to a molecular-level understanding of the structural characteristics required of high temperature fuel cell PEMs. His numerous publications and presentations assist other researchers in their own efforts to the overcome barriers in developing PEMs. Qifei has published six papers in archival refereed journals including the J. Phys. Chem. B, Phys. Rev. E, J. Chem. Phys. and Macromolecules, with two more manuscripts currently under review. He has authored or co-authored eleven technical presentations.
