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Physical Properties of Low-Molecular Weight Polydimethylsiloxane Fluids

Roberts, Christine C.; Graham, Alan G.; Nemer, Martin N.; Phinney, Leslie M.; Garcia, Robert M.; Soehnel, Melissa M.; Stirrup, Emily K.

Physical property measurements including viscosity, density, thermal conductivity, and heat capacity of low-molecular weight polydimethylsiloxane (PDMS) fluids were measured over a wide temperature range (-50°C to 150°C when possible). Properties of blends of 1 cSt and 20 cSt PDMS fluids were also investigated. Uncertainties in the measurements are cited. These measurements will provide greater fidelity predictions of environmental sensing device behavior in hot and cold environments.

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TYPE SAND Report YEAR 2017
OSTIDOI

Final report : CO2 reduction using biomimetic photocatalytic nanodevices

Song, Yujiang S.; Garcia, Robert M.; Shelnutt, John A.

Nobel Prize winner Richard Smalley was an avid champion for the cause of energy research. Calling it 'the single most important problem facing humanity today,' Smalley promoted the development of nanotechnology as a means to harness solar energy. Using nanotechnology to create solar fuels (i.e., fuels created from sunlight, CO{sub 2}, and water) is an especially intriguing idea, as it impacts not only energy production and storage, but also climate change. Solar irradiation is the only sustainable energy source of a magnitude sufficient to meet projections for global energy demand. Biofuels meet the definition of a solar fuel. Unfortunately, the efficiency of photosynthesis will need to be improved by an estimated factor of ten before biofuels can fully replace fossil fuels. Additionally, biological organisms produce an array of hydrocarbon products requiring further processing before they are usable for most applications. Alternately, 'bio-inspired' nanostructured photocatalytic devices that efficiently harvest sunlight and use that energy to reduce CO{sub 2} into a single useful product or chemical intermediate can be envisioned. Of course, producing such a device is very challenging as it must be robust and multifunctional, i.e. capable of promoting and coupling the multi-electron, multi-photon water oxidation and CO{sub 2} reduction processes. Herein, we summarize some of the recent and most significant work towards creating light harvesting nanodevices that reduce CO{sub 2} to CO (a key chemical intermediate) that are based on key functionalities inspired by nature. We report the growth of Co(III)TPPCl nanofibers (20-100 nm in diameter) on gas diffusion layers via an evaporation induced self-assembly (EISA) method. Remarkably, as-fabricated electrodes demonstrate light-enhanced activity for CO{sub 2} reduction to CO as evidenced by cyclic voltammograms and electrolysis with/without light irradiation. To the best of our knowledge, it is the first time to observe such a light-enhanced CO{sub 2} reduction reaction based on nanostructured cobalt(III) porphyrin catalysts. Additionally, gas chromatography (GC) verifies that light irradiation can improve CO production by up to 31.3% during 2 hours of electrolysis. In addition, a variety of novel porphyrin nano- or micro-structures were also prepared including nanospheres, nanotubes, and micro-crosses.

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TYPE SAND Report YEAR 2009
OSTIDOI
20 Results
20 Results