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Publications

Search Publications by David VanderHart

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Displaying 1 - 25 of 68

Measuring domain sizes and compositional heterogeneities in P3HT-PCBM bulk heterojunction thin films with 1H spin diffusion NMR spectroscopy

March 21, 2012
Author(s)
Ryan C. Nieuwendaal, Hyun Wook Ro, David Germack, Regis J. Kline, Calvin Chan, Amit K. Agrawal, David J. Gundlach, David L. VanderHart, Dean M. DeLongchamp
In this manuscript we show that 1H spin diffusion NMR is a valuable method for estimating the domain sizes in thin films of a polymer-fullerene blend for bulk heterojunction (BHJ) photovoltaics. Variations in common BHJ film processing parameters have

NMR Characterization of the Formation Kinetics and Structure of Di-O-Benzylidene Sorbitol Gels Self-Assembled in Organic Solvents

January 19, 2011
Author(s)
David L. VanderHart, Jack F. Douglas, Steven D. Hudson, Joseph M. Antonucci, Elizabeth A. Wilder
The molecule 1,3:2,4-Di-O-Benzylidene sorbitol (DBS) is a common gelator that forms thermally reversible gels in diverse organic solvents. Solid state 13C and proton NMR techniques, along with electron microscopy, are utilized in an exploratory study of

Photoresist latent and developer images as probed by neutron reflectivity methods

September 16, 2010
Author(s)
Vivek M. Prabhu, Shuhui Kang, David L. VanderHart, Eric K. Lin, Wen-Li Wu
Photoresist materials enable the fabrication of advanced integrated circuits with ever decreasing feature sizes. As next-generation light sources are developed, using extreme ultraviolet light of wavelength 13.5 nm, these highly-tuned formulations must

Synthetic Mica: A Very Promising Substrate for Studying Solid Thin Films by Proton NMR

August 25, 2009
Author(s)
David L. VanderHart, Vivek M. Prabhu, Kristopher Lavery, Cindi L. Dennis
We demonstrate that a synthetic fluorophlogopite mica can be used as a proton-free, diamagnetic substrate for examining solid thin-film samples using conventional solid-state proton NMR experiments. The context of this work extends previous NMR studies on

Thin Film Solid State Proton NMR Measurements Using A Synthetic Mica Substrate: Polymer Blends

August 25, 2009
Author(s)
David L. VanderHart, Vivek M. Prabhu, Kristopher Lavery, Cindi L. Dennis, Ashwin Rao, Eric K. Lin
We demonstrate that a synthetic fluorophlogopite mica can be used as a proton-free, diamagnetic substrate for examining solid thin-film samples using conventional solid-state proton nuclear magnetic resonance (NMR) experiments. The context of this work

Quantitative Measurement of the Polydispersity in the Extent of Functionalization of Glass Forming Resorcinarenes

May 1, 2009
Author(s)
William E. Wallace, Kathleen M. Flynn, Charles M. Guttman, David L. VanderHart, Vivek M. Prabhu, Anuja De Silva, Nelson Felix, Christopher K. Ober
The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring their molecular mass distribution with matrix-assisted laser desorption/ionization time of flight mass spectrometry. A mathematical method for

FTIR measurements of compositional heterogeneities

February 25, 2007
Author(s)
Shuhui Kang, B D. Vogt, Wen-Li Wu, Vivek M. Prabhu, David L. VanderHart, Ashwin Rao, Eric K. Lin, Karen Turnquest
A general approach to characterize compositional heterogeneity in polymer thin films using Fourier transform infrared (FTIR) spectroscopy has been demonstrated Polymer films with varying degrees of heterogeneity were prepared using a model chemically

Characterization of Compositional Heterogeneity in Chemically Amplified Photoresist Polymer Thin Films with Infrared Spectroscopy

February 9, 2007
Author(s)
Shuhui Kang, B D. Vogt, Vivek M. Prabhu, Eric K. Lin, Wen-Li Wu, David L. VanderHart, Ashwin Rao, Karen Turnquest
We demonstrate a general approach to characterize compositional heterogeneity in polymer thin films using Fourier transform infrared (FTIR) spectroscopy. Polymer films with varying degrees of heterogeneity were prepared using a model chemically amplified

Dielectric Study of the Anti-Plasticization of Trehalose by Glycerol

January 1, 2006
Author(s)
A Anopchenko, Tatiana Psurek, David L. VanderHart, Jack F. Douglas, Jan Obrzut
Recent measurements have suggested that the antiplasticizing effect of glycerol on trehalose can significantly increase the preservation times of proteins stored in this type of preservative formulation. In order to better understand the physical origin of

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Interlaboratory Comparison of Mixtures of Polystyrene With Different End Groups: Statistical Analysis of Mass Fractions and Mass Moments

July 1, 2005
Author(s)
Charles M. Guttman, S Wetzel, Kathleen M. Flynn, B M. Fanconi, David L. VanderHart, William E. Wallace
A matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) interlaboratory comparison was conducted on mixtures of synthetic polymers having the same repeat unit and closely matching molecular mass distributions but with

Effect of Tacticity on the Structure of Poly (1-Octadecene)

September 1, 2004
Author(s)
David L. VanderHart, E Perez, A Bello, G B. Vasquez, Manuel A. Quijada
A sample of poly(1-octadecene), synthesized with a highly active heterogeneous Ziegler-Natta catalyst, has been fractionated with n-heptane, giving soluble and insoluble fractions. Both fractions and the original polymer have been characterized by SEC

Proton NMR Determination of Miscibility in a Bulk Model Photoresist System Poly (4-Hydroxystyene) and the Photoacid Generator, Di(t-butylphenyl) Iodonium Perfluorooctane Sulfonate

July 13, 2004
Author(s)
David L. VanderHart, Vivek M. Prabhu, Eric K. Lin
The intimacy of component mixing in 2 blends of poly(4-hydroxystyrene) (PHS) and a photoacid generator (PAG), di(t-butylphenyl) iodonium perfluorooctane sulfonate (PFOS) were studied by solid state proton NMR. Mass ratios were 91/9 and 85/15 PHS/PFOS

Solid-Phase ATRP Synthesis of Peptide-Polymer Hybrids

March 1, 2004
Author(s)
Ying Mei, Kathryn L. Beers, H M. Byrd, David L. VanderHart, N. R. Washburn
A versatile methodology for preparing hybrid biomaterials by atom transfer radical polymerization from resin-supported peptides has been established. As an example, we have synthesized a GRGDS-functionalized poly(2-hydroxyethyl methacrylate). The peptide

International Interlaboratory Comparison of Mixtures of Polystyrenes With Different End Groups Obtained by Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS): Preliminary Results

January 1, 2004
Author(s)
Charles M. Guttman, S Wetzel, Kathleen M. Flynn, B M. Fanconi, William E. Wallace, David L. VanderHart
NIST has sponsored a MALDI-TOF-MS interlaboratory comparison of mixtures of polymers of the same repeat unit with closely matching molecular masses but with different end groups. This interlaboratory comparison was designed to see how well a group of labs

INVESTIGATION OF NANODISPERSION IN POLYSTYRENE -MONTMORILLONITE NANOCOMPOSITES BY SOLID STATE NMR

December 15, 2003
Author(s)
S Bourbigot, Jeffrey W. Gilman, David L. VanderHart, W H. Awad, Rick D. Davis, A B. Morgan, C A. Wilkie
Nanocomposites result from combinations of materials with vastly different properties at the nanometer scale. These materials exhibit many unique properties, such as improved thermal stability, reduced flammability, and improved mechanical properties. Many

Certification of a Polystyrene Synthetic Polymer, SRM 2888

November 1, 2003
Author(s)
Charles M. Guttman, William R. Blair, B M. Fanconi, R J. Goldschmidt, William E. Wallace, S Wetzel, David L. VanderHart
The certification of a polystyrene standard reference material, SRM 2888, is described. The Mw of SRM 2888 was determined by light scattering to be 7.19 x 10+3 g/mol with a sample standard deviation of 0.14 x 10+3 g/mol. A combined expanded uncertainty for

High Throughput Methods for Polymer Nanocomposites Research: Extrusion, Nmr Characterization and Flammability Property Screening.

November 1, 2003
Author(s)
Jeffrey W. Gilman, S Bourbigot, John R. Shields, Marc R. Nyden, Takashi Kashiwagi, Rick D. Davis, David L. VanderHart, W Demory, C A. Wilkie, A B. Morgan, J R. Harris, R Lyon
Several, recent, revolutionary advances in combinatorial (or high throughput, HT) polymer science have appeared in the literature, which significantly accelerate the rate of data generation. Although these new HT approaches may in part have been inspired