last update: March 28, 2001
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STC-ERSP Program Details Principal Investigator: R. W. Murray Project Title: Electrochemical Measurements In CO2 (Former Prog #26) Research Plan Connectivity Outreach Components Requested Budget Allocation - Year 1 Plans for Additional Funding Research Plan Overall objectives I propose to adapt methods and strategies that have been developed in my laboratory for electrochemistry in semi-solid, ionically poorly conductive media, to CO2 media. The objectives are to devise electrochemical tools that can be used i) for fundamental studies of interfacial kinetics, of mass transport dynamics, and of solvation phenomena, ii) for developing ways to measure chemical interactions of relevance to organized, polymeric, and nanoscopic systems in CO2, and iii) for analytical approaches to measure the progress and state of chemical reactions in CO2. Relation to overall objectives of the Center Progress in basic and applied aspects of chemistry in CO2 is directly related to the ability to measure chemical phenomena in that medium; we seek to add electrochemical methods to the experimental capacity to investigate such phenomena. The kinds of measurements that we seek are relevant to cross-cutting themes in the Center, and include mass transport dynamics, surfactant behavior, interfacial solvation and kinetics, plasticization dynamics, partition of probes between CO2 and polymer phases, partition, and electrochemical potentials and stability of reactive species. Approach and timelines The initial phase of the research will be adaptation of existing electrochemical microelectrodes and microcells to the CO2 environment--this includes working through materials compatibilities, assessing different strategies to combat poor ionic conductivity, and weighing transient versus steady state voltammetry tatics. The ionic conductivity strategies include coating the electrode(s) with a swellable ionically conductive film, using ionic fluoro-surfactants as supporting electrolyte in the CO2 "bulk" phase, and using interdigitated array electrodes in steady state mode. The criteria of progress are obtaining electrochemical transport, kinetic, and partition data that are quantitatively interpretable. The second research phase-- in year 2 or 3--would begin to apply measurement successes to specific chemical interaction issues. These could include measuring the degree of CO2 swelling/plasticization of polymer phases by measuring the diffusion rates of redox probes in them, study of micellar encapsulation of redox probes with surfactants (reactivity, reaction kinetics), and flow injection analysis of specific components of polymerization-relevant CO2 phases. The later years would turn to either more detailed studies prompted by results of the second phase, or to investigation of the electrochemical and chemical stability of very high and low oxidation state chemical systems in CO2, a point of interest given the low reactivity of CO2 as either a reductant or oxidant medium. Other issues of materials chemistry interest would include electrochemistry and chemistry of hydrophobically-coated metal nanoparticles dissolved in CO2 (we have extensive interests in nanoparticle electrochemistry), of electrochemically-generated luminescence, and of molten molecular salts involving phthalocyanines, metal bipyridine complexes, and DNA. The latter are new materials that we have recently prepared, using newly devised chemistry of ionic PEO oligomers. Thrust area of this proposal Thrust Area 4 although in fact our plans are broader and more encompassing. Connectivity Collaborators, multi-institutional, multi-disciplinary components Fixed notions of collaborations are often akin to the set-minds of 1800's British battle plans. My laboratory has historically collaborated freely, but opportunistically, whenever we have chemistry to bring to the table, or methodology, and we perceive a colleague with the complementary strength available. In the CO2 setting, we believe such collaborations will emerge naturally as we develop measurement tools that are of interest to others within the community. However some important and crucial interactions are obvious and include: a) the DeSimone group as a source of advice concerning CO2 and electrode materials and sealants compatibilities, and as a source of surfactants as electrolytes (and/or concerning their synthesis), and b) electrochemists who join the overall project at NCSU and who have common interests. Related work in other thrust areas There is no other work within the STC directly related to electrochemistry, but development of new electrochemcial measurement capabilities should be broadly applicable within the Center. Sharing of resources (students, supplies, equipment, etc.) As has been the case for decades, my laboratory has shared our measurement skills freely with others in the local scientific community. We do not however, envision acting as an electrochemical measurement service laboratory if it proves debilitating to the objectives cited above. Outreach Components My laboratory has for the past several years been the focus of a group of undergraduates who have interest in promoting interest in science in primary education settings (Science Outreach Program). I am their nominal faculty advisor. I have also acted as a NC Math and Science Mentor in the past year. Requested Budget Allocation - Year 1 Personnel salaries
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