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Search Publications

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Displaying 551 - 575 of 1856

Classification of Semiconducting Polymeric Mesophases to Optimize Device Post-Processing

August 17, 2015
Author(s)
Chad R. Snyder, Regis J. Kline, Dean M. DeLongchamp, Ryan C. Nieuwendaal, Lee J. Richter, Martin Heeney, Iain McCulloch
Semiconducting polymers form a variety of phases and mesophases that respond differently to post-deposition solvent or thermal treatments. Here it is shown that classification of these materials into their appropriate mesophases can be a useful tool to

In-Situ Method for Measuring the Mechanical Properties of Nafion Thin Films during Hydration Cycles

August 15, 2015
Author(s)
Kirt A. Page, Jae W. Shin, Scott Eastman, Brandon W. Rowe, Sangcheol Kim, Ahmet Kusoglu, Kevin G. Yager, Gery R. Stafford
Perfluorinated ionomers, in particular Nafion, are an essential component in hydrogen fuel cells, as both the proton exchange membrane and the binder within the catalyst layer. During normal operation of a hydrogen fuel cell the ionomer will progressively

Infrared Imaging and Spectroscopy Beyond the Diffraction Limit

July 22, 2015
Author(s)
Andrea Centrone
Progress in nanotechnology is enabled by and dependent on the availability of measurement methods with spatial resolution commensurate with nanomaterials’ length scales. Chemical imaging techniques, such as scattering scanning near-field optical microscopy

Aging of Polymeric Films used in Protective Glazing Systems

July 7, 2015
Author(s)
Christopher C. White, Donald L. Hunston, Kar T. Tan
The toughness of polymer and glass laminates or win-dow glazing, are used to protect buildings and occupants from shattered glass resulting from natural disasters (e.g., hurricanes, tornadoes, seismic events), and intentional events (e.g., robbery

Tuning Open-Circuit Voltage in Organic Solar Cells with Molecular Orientation

June 24, 2015
Author(s)
Brent Kitchen, Omar Awartani, Regis J. Kline, Terry McAfee, Harald Ade, Brendan T. O'Connor
The role of molecular orientation of a polar conjugated polymer in a polymer-fullerene organic photovoltaic (OPV) cells is investigated. A planar heterojunction (PHJ) OPV cell composed of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid

Mesomorphic Pathway in Early Stage Crystallization of Polyethylene

June 18, 2015
Author(s)
Kalman D. Migler, Angela R. Hight Walker, Anthony P. Kotula
The kinetic pathway by which a molten polymer transforms into a multi-length scale semi-crystalline structure upon cooling is an unsolved problem in polymer physics, yet it is critical to the processing, properties and ultimate performance of these

Rheology and Dynamics of Colloidal Superballs

June 9, 2015
Author(s)
John R. Royer, George L. Burton, Daniel L. Blair, Steven D Hudson
Recent advances in colloidal synthesis make it possible to generate a wide array of precisely controlled, non-spherical, shaped particles. However, relatively little is known about the role that particle shape plays in the dynamics of colloidal suspensions

Small-Angle X-ray Scattering of Ionic Liquids

June 1, 2015
Author(s)
Fan Zhang, Joshua A. Hammons, Jan Ilavsky
Small angle X-ray scattering (SAXS) is a powerful technique that is used to resolve the size and structure of phases on the nanometer scale, within a sample. While these features may also be observed with other techniques, such as: electron microscopy or

Multi-scale measurement for tensile behaviors of glass fiber composites at high rate loading: Fiber fragmentation behaviors in epoxy resin

May 19, 2015
Author(s)
Jae Hyun Kim, Steven P. Mates, Nathanael A. Heckert, Walter G. McDonough, Gale A. Holmes
High strength and light weight composite materials used in various structural components of aviation and automotive applications deform under high rate loading conditions during collision. Since composite structures using continuous fibers are constituted

ELEVATED TEMPERATURE ADHESION TESTING OF SPRAY-APPLIED FIRE-RESISTIVE MATERIALS

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Walter E. Byrd
Effective fire protection of steel can be fully realized when spray-applied fire resistive materials (SFRMs) are bonded sufficiently to structural steel during the event of fire. The adhesion mechanisms and characterization at elevated temperatures

MECHANISMS OF CRITICALITY IN ENVIRONMENTAL ADHESION LOSS

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Kristen L. Steffens, Deborah S. Jacobs, Bulent Akgun, Vogt D. Bryan
Moisture attack on adhesive joints is a long-standing scientific and engineering problem. A particularly interesting observation is that when the moisture level in certain systems exceeds a critical concentration, the bonded joint shows a dramatic loss of

Prediction of Sealant Modulus Change due to Outdoor Weathering

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Adam L. Pintar, James J. Filliben
An empirically-based model has been created to predict the change in modulus for a sealant exposed to outdoor weathering. The underlying high precision data supporting this model was obtained using the NIST SPHERE (Simulated Photo degradation by High

On-wafer Magnetic Resonance of Magnetite Nanoparticles

May 11, 2015
Author(s)
Charles A. Little, Stephen E. Russek, James C. Booth, Pavel Kabos, Robert J. Usselman
Magnetic resonance measurements of ferumoxytol and TEMPO were made using an on-wafer transmission line technique with a vector network analyzer, allowing for broadband measurements of small sample volumes (4 nl) and a small numbers of spin (1 nmole). On

Free Space Microwave Non Destructive Characterization of Composite Materials

May 4, 2015
Author(s)
Jan Obrzut, Ahmed M. Hassan, Edward J. Garboczi
We present a free-space microwave experimental measurement system for the non-destructive testing of composite materials. The system operates in the Q- frequency band of 30 GHz to 50 GHz with fixed wave propagation distance between free-space antennas
Displaying 551 - 575 of 1856