Structural Evolution of Porous Coordination Polymers upon Chemical Exposure

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TECHNICAL SUMMARY:The over-arching goal of this research is to develop a detailed, molecular level understanding of an emerging class of ultrahigh performance sorbents named Microporous Coordination Polymers (MCPs). MCP sorbent performance derives from their high fractional volume (porosity) of tiny, nanometer-sized pores resulting in exceedingly high specific surface areas. An understanding of how these materials can adsorb such enormous amounts of gases and the chemical/physical basis for selective uptake are the major thrusts of the proposed research. In particular, the fundamental role of pore size, pore architecture, and pore interconnectedness will be observed for the first time during the actual processes of gas adsorption and solvent removal. Enabling this unique viewpoint is the first use in MCPs of positron annihilation lifetime spectroscopy, an antimatter probe of porous materials recently developed to characterize microporous thin film dielectric insulators in microelectronic devices. Adoption of this technique has the potential to transform how researchers probe porosity in sorbents. Only by understanding how changes on the microscale and nanoscale exert an effect on apparent porosity can the best modes of exploiting existing MCPs be realized. Ultimately these results will be of practical use to guide the synthesis of new materials. MCP?s are expected to find broad application in energy research (gas storage) and environmental research (gas purification) and since MCPs are now being commercialized they are at the point where direct impact on society can and will be felt.NON-TECHNICAL SUMMARYThis research brings together chemists and physicists in an effort to transform the study of ultrahigh performance sorbents?the nanomaterials that are themselves transforming the field of chemical separations. This unique collaboration seeks to use powerful antimatter probe techniques recently developed to study newly engineered porous insulators in microchips to provide unprecedented structural characterization. These highly porous sorbents are expected to find broad application in alternative energy (gas storage) and industrial processes (gas purification) and since they are now beginning to be commercialized they are at the point where direct impact on society will be felt. The impact of this research is totally dependent on the successful interaction of chemists and physicists. Graduate and undergraduate students will cross discipline boundaries to learn in a broadly diverse and collaborative environment involving frequent interaction with industry. For these reasons the potential for obtaining transformative research results is high. However, this will only be possible if the properties of the materials are sufficiently well understood to allow widespread deployment in new more efficient processes. It is clear that sorbent technology has not yet achieved this point, but the proposed research will do much to enable reaching this goal.