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Search Publications by: Jeffrey Fagan (Fed)

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Displaying 51 - 75 of 96

Analyzing Surfactant Structures on Length and Chirality Resolved (6,5) Single-Wall Carbon Nanotubes by Analytical Ultracentrifugation

March 26, 2013
Author(s)
Jeffrey A. Fagan, Ming Zheng, Jeffrey R. Simpson, Vinayak Rastogi, Constantine Y. Khripin, Carlos A. Silvera Batista, Angela R. Hight Walker
The structure and density of the bound interfacial surfactant layer and associated hydration shell were investigated using analytical ultracentrifugation for length and chirality purified (6,5) single-wall carbon nanotubes (SWCNTs) in three different bile

Salt-Specific Effects in Aqueous Dispersions of Carbon Nanotubes

February 13, 2013
Author(s)
Jeffrey A. Fagan, Carlos A. Silvera Batista, Alberto Striolo, Naga Rajesh Tummala, Manaswee Suttipong
Tremendous progress has been made to stabilize carbon nanotube dispersions using surfactants, although many questions await answer to design surfactant formulations that selectively stabilize nanotubes mono-dispersed in diameter and chirality. Stimulated

Fourth NIST Workshop on Carbon Nanotubes: Chirality Measurements

January 30, 2013
Author(s)
Jeffrey A. Fagan
On September 23rd and 24th, 2010, the National Institute of Standards and Technology (NIST) hosted the fourth in a series of workshops addressing measurement needs for single wall carbon nanotubes (SWCNTs). Attendees representing an international community

High Resolution Length Fractionation of Surfactant Dispersed Carbon Nanotubes

December 23, 2012
Author(s)
Constantine Y. Khripin, Xiaomin X. Tu, Jeffrey A. Fagan, Ming Zheng
Length fractionation of colloidal carbon nanotube dispersions is required for many studies. Size- exclusion chromatography (SEC) has been reported as a reliable method for high resolution length fractionation of DNA-dispersed single-wall carbon nanotubes

Concentration Measurement of Length-Fractionated Colloidal Single-Wall Carbon Nanotubes

September 20, 2012
Author(s)
Constantine Y. Khripin, Xiaomin X. Tu, John Howarter, Jeffrey A. Fagan, Ming Zheng
Determination of the colloid concentration for a given single-wall carbon nanotube (SWCNT) dispersion is a basic requirement for many studies. The commonly used optical absorption based concentration measurement is complicated by the spectral change due to

Determination of Moisture Content of Single-Wall Carbon Nanotubes

October 17, 2011
Author(s)
Rolf L. Zeisler, Rabia Oflaz, Ralph E. Sturgeon, Rick L. Paul, Brian E. Lang, Jeffrey A. Fagan, Joseph W. Lam, Anthony Windust, P Grinberg, Benoit Simard, Christopher T. Kingston
Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides for a direct measure of the water content and was used for benchmarking against results

Measuring agglomerate size distribution and dependence of localized surface plasmon resonance absorbance on gold nanoparticle agglomerate size using analytical ultracentrifugation

September 3, 2011
Author(s)
Justin M. Zook, Vinayak Rastogi, Robert I. MacCuspie, Athena M. Keene, Jeffrey A. Fagan
Nanoparticles frequently agglomerate when dispersed into relevant biological and environmental media, with the resulting change to the effective size distribution dramatically affecting the potential nanotoxicity and the absorbance for biosensor

Separation of Empty and Water-Filled Single-Wall Carbon Nanotubes

April 11, 2011
Author(s)
Jeffrey A. Fagan, Jeffrey R. Simpson, JiYeon Huh, Jeffrey Blackburn, Larsen A. Brian, Josh M. Holt, Angela R. Hight Walker
The separation of empty and water-filled laser ablation and electric arc synthesized nanotubes is reported. Centrifugation of these large-diameter nanotubes dispersed with sodium deoxycholate using specific conditions produces isolated bands of empty and

Flexure-induced structural and electronic changes in polymer supported membranes of length purified single-wall carbon nanotubes

February 22, 2011
Author(s)
John M. Harris, Ganjigunte R. Iyer, Daneesh O. Simien, Jeffrey Fagan, JiYeon Huh, Jun Y. Chung, Steven Hudson, Jan Obrzut, Jack F. Douglas, Christopher Stafford, Erik K. Hobbie
Thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are uniaxially compressed by depositing them on prestretched polymer substrates. Upon release of the strain, the topography, microstructure and conductivity of the films are

Elemental Analysis of a Single-Walled Carbon Nanotube Candidate Reference Material

October 15, 2010
Author(s)
Rolf L. Zeisler, Rick L. Paul, Rabia Oflaz, Lee L. Yu, Jacqueline L. Mann, William R. Kelly, Brian E. Lang, Stefan D. Leigh, Jeffrey A. Fagan
A material containing single-walled carbon nanotubes (SWCNTs) together with other carbon species, cata-lyst residues, and trace element contaminants has been prepared by the National Institute of Standards and Technology for characterization and

lSPR Study of DNA Wrapped Single Wall Carbon Nanotube (ssDNA-SWCNT) Adsorption on a Model Biological (Collagen) Substrate

September 20, 2010
Author(s)
Jung Jin Park, Jeffrey Fagan, JiYeon Huh, Kalman D. Migler, Alamgir Karim, Dharmaraj Raghavan
The kinetics of single stranded-DNA dispersed single wall carbon nanotubes (SWCNTs) adsorption onto an immobilized collagen layer in a microfluidic channel was probed using surface plasmon resonance (SPR) imaging. The adsorption was measured for a range of

Carbon Nanotubes: Measuring Dispersion and Length

August 26, 2010
Author(s)
Jeffrey A. Fagan, Barry J. Bauer, Erik K. Hobbie, Matthew Becker, Angela R. Hight Walker, Jeffrey R. Simpson, Jae H. Chun, Jan Obrzut, Vardhan Bajpai, Frederick R. Phelan Jr., Daneesh O. Simien, JiYeon Huh, Kalman D. Migler
Advanced technological uses of single-wall carbon nanotubes (SWCNTs) rely on the production of single length and chirality populations that are currently only available through liquid phase post processing. The foundation of all of these processing steps

Separation and Characterization of Double Wall Carbon Nanotube Sub-Populations

July 8, 2010
Author(s)
JiYeon Huh, Angela R. Hight Walker, Hyun W. Ro, Jan Obrzut, Jeffrey Fagan
We present the separation of surfactant encapsulated double wall carbon nanotubes (DWCNTs) synthesized by the high pressure carbon monoxide decomposition (HiPco) process by length and electronic characteristics using density gradient ultracentrifugation

Large Magnetic Susceptibility Anisotropy of Metallic Carbon Nanotubes

July 2, 2010
Author(s)
Jeffrey A. Fagan, Erik K. Hobbie, Jun Kono, Thomas Searles, Y Imanaka, T Takamasu, H Ajiki
Through magnetic linear dichroism spectroscopy, the magnetic susceptibility anisotropy of metallic single-walled carbon nanotubes has been extracted and found to be 2-4 times greater than values for semiconducting single-walled carbon nanotubes. This large

Wrinkling and Strain Softening in Single-Wall Carbon Nanotube Membranes

March 26, 2010
Author(s)
Erik K. Hobbie, Daneesh O. Simien, Jeffrey A. Fagan, JiYeon Huh, Jun Y. Chung, Steven D. Hudson, Jan Obrzut, Jack F. Douglas, Christopher M. Stafford
Ultrathin layers of single-wall carbon nanotubes (SWCNTs) show considerable promise for applications ranging from fuel-cell membranes and biochemical sensors to bioactive films and transparent electrodes. The high conductivity and extreme anisotropy of

Methods for TEM analysis of NIST’s SWCNT SRM

March 25, 2010
Author(s)
Roy H. Geiss, Elisabeth Mansfield, Jeffrey A. Fagan
The National Institute of Standards and Technology (NIST) is developing a series of single-walled carbon nanotube, SWCNT, reference materials, RMs, to provide researchers with well characterized materials for their applications. The SWCNT reference

Nanotube Length Distributions Measured from Suspension by Electrospray-Differential Mobility Analysis

December 4, 2009
Author(s)
Leonard F. Pease III, De-Hao D. Tsai, Jeffrey A. Fagan, Barry J. Bauer, Rebecca A. Zangmeister, Michael J. Tarlov, Michael R. Zachariah
We present the first systematic characterization of well dispersed, length sorted single-walled carbon nanotubes (SWCNTs) by electrospray-differential mobility analysis (ES-DMA). Although understanding geometric properties of SWCNTs including their length

Sample Preparation Protocols for Realization of Reproducible Characterization of Single-walled Carbon Nanotubes

December 1, 2009
Author(s)
Angela R. Hight Walker, Jeffrey A. Fagan, Stephanie A. Hooker, Michael T. Postek, Stephen A. Wise, Andras Vladar, Rolf L. Zeisler
Harmonized sample pre-treatment is an integral first step in ensuring metrological quality of measurements as regards repeatability, inter-laboratory reproducibility and commutability. The development of standard preparation methods for SWCNT samples is