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Investigations into Moisture Diffusion of Fiber Reinforced Composite Materials

Reyes, Karla R.; Reyes, Karla R.; Pavia Sanders, Adriana P.; Massey, Lee T.; Warnock, Corinne M.; Ward, Donald K.; Withey, Elizabeth A.; Chames, Jeffery M.; Briggs, Timothy B.

The moisture absorption behavior of two fiber reinforced composite materials was evaluated in a unidirectional manner The flat materials were exposed to varying humidity and temperature conditions inside of an environmental chamber in order to determine their effective moisture equilibrium (M m ) and moisture absorption rate (D z ). Two-ply (thin) and four-ply (thick) materials were utilized to obtain M,,, and Dz, respectively. The results obtained from laboratory work were then compared to modeling data to better understand the material properties. Predictions capabilities were built to forecast the maximum moisture content, time required for saturation, and the moisture content at any given humidity and temperature. A case study was included to demonstrate this capability. Also of interest were cubed samples to investigate directionality preferences in water immersion studies. Several coatings were evaluated for their water permeation properties. Further dissemination authorized to the Department of Energy and DOE contractors only; other requests shall be approved by the originating facility or higher DOE programmatic authority.

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TYPE SAND Report YEAR 2018
OSTIDOI

Composite WO3/TiO2 nanostructures for high electrochromic activity

ACS Applied Materials and Interfaces

Reyes, Karla R.; Stephens, Zachary D.; Robinson, David R.

A composite material consisting of TiO2 nanotubes (NT) with WO3 electrodeposited on its surface has been fabricated, detached from its Ti substrate, and attached to a fluorine-doped tin oxide (FTO) film on glass for application to electrochromic (EC) reactions. Several adhesion layers were tested, finding that a paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length and WO3 concentration on the EC performance were studied. As a result, the composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast, and longer memory time compared with the pure WO3 and TiO2 materials

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TYPE Journal Article YEAR 2015
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Theoretical and experimental studies of electrified interfaces relevant to energy storage

Hayden, Carl C.; Templeton, Jeremy A.; Jones, Reese E.; Kliewer, Christopher J.; Sasaki, Darryl Y.; Reyes, Karla R.

Advances in technology for electrochemical energy storage require increased understanding of electrolyte/electrode interfaces, including the electric double layer structure, and processes involved in charging of the interface, and the incorporation of this understanding into quantitative models. Simplified models such as Helmholtz's electric double-layer (EDL) concept don't account for the molecular nature of ion distributions, solvents, and electrode surfaces and therefore cannot be used in predictive, high-fidelity simulations for device design. This report presents theoretical results from models that explicitly include the molecular nature of the electrical double layer and predict critical electrochemical quantities such as interfacial capacitance. It also describes development of experimental tools for probing molecular properties of electrochemical interfaces through optical spectroscopy. These optical experimental methods are designed to test our new theoretical models that provide descriptions of the electric double layer in unprecedented detail.

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TYPE SAND Report YEAR 2013
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20 Results
20 Results