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Displaying 1376 - 1400 of 1938

Measurement of Reactivity Ratios in Surface-Initiated Copolymerization

August 21, 2007
Author(s)
Derek L. Patton, Kirt A. Page, Chang Xu, Kirsten Genson, Michael J. Fasolka, Kathryn L. Beers
This work describes a new approach to measure monomer reactivity ratios from surface-initiated copolymerizations using x-ray photoelectron spectroscopy. Styrene/methyl methacrylate statistical copolymer brushes were prepared from various monomer feeds by

Relaxation Behavior of Polymer Structures Fabricated by Nanoimprint Lithography

August 14, 2007
Author(s)
Yifu Ding, Hyun Wook Ro, Thomas A. Germer, Jack F. Douglas, Brian C. Okerberg, Alamgir Karim, Christopher L. Soles
We study the decay of the imprinted polystyrene (PS) patterns under thermal annealing using light diffraction. The first order diffraction intensity from the imprinted gratings was measured as a function of annealing time. Local intensity maximum is

Microfluidic Dynamic Light Scattering Used for High Throughput Measurements

July 10, 2007
Author(s)
Thomas Q. Chastek, Kathryn L. Beers, Eric J. Amis
When diluted in some solvents, surfactants and block copolymers self-assemble into micelles or vesicles of about 10-100 nm in size. There is a great deal of interest in micelles and vesicles because they are widely used in the formulations industry, and

Characterization of the Potential Energy Landscape in an Antiplasticized Polymer

July 6, 2007
Author(s)
Robert A. Riggleman, Jack F. Douglas, J J. de Pablo
Transition state searches have been performed on model coarse-grained polymer systems, and the results compared to those of an antiplasticized polymer system, which have been previously shown to be fragile and strong glass-forming systems, respectively. It

Tuning Polymer Melt Fragility With Antiplasticizer Additives

June 19, 2007
Author(s)
Robert A. Riggleman, Jack F. Douglas, J J. de Pablo
A polymer-diluent model exhibiting antiplasticization has beendeveloped and characterized by molecular dynamics simulations. Antiplasticizer molecules are shown to decrease the glass transition temperature Tg, but to increase the elastic moduli of the

Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites

June 13, 2007
Author(s)
Takashi Kashiwagi, Jeffrey Fagan, Jack F. Douglas, Kazuya Yamamoto, N. Alan Heckert, Stefan D. Leigh, Jan Obrzut, Fangming Du, Minfang Mu, Sheng Lin-Gibson, K Winey, R Haggenmueller
Particle spatial dispersion is a crucial characteristic of polymer composite materials and this property is recognized as especially important innanocomposite materials due to the general tendency of nanoparticles to aggregate under processing conditions

An Apparatus For Folding Yarns And Woven Fabrics Of Ballistic Fibers

June 4, 2007
Author(s)
Walter G. McDonough, Jae Hyun Kim, Nolan J. Brandenburg, William R. Blair, Gale A. Holmes
Folding of ballistic fibers comprising soft body armor may be a factor in the performance deterioration that has been observed in used soft body armor. To quantify the impact of this mechanism, an apparatus was designed and built to simulate the folding

Numerical Optimization of Matrix-Assisted Laser Desorption/Ionization Time-of- Flight Mass Spectrometry: Application to Synthetic Polymer Molecular Mass Distribution Measurement

May 26, 2007
Author(s)
William E. Wallace, Charles M. Guttman, Kathleen M. Flynn, Anthony J. Kearsley
A novel approach is described for the selection of optimal instrument parameters that yield a mass spectrum which best replicates the molecular mass distribution of a synthetic polymer. The application of implicit filtering algorithms is shown to be a

Polymer Viscoelasticity and Residual Stress Effects on Nanoimprint Lithography

May 24, 2007
Author(s)
Yifu Ding, Hyun Wook Ro, Jack F. Douglas, Ronald L. Jones, Daniel R. Hines, Alamgir Karim, Christopher L. Soles
We examine the influence of viscoelastic effects on the stability of nanoimprinted polymer films. The decay of features for polymers below the critical entanglement molecular mass at elevated temperatures is determined by simple surface tension and the

Measurement of Single Wall Nanotube Dispersion by Size Exclusion Chromatography

May 9, 2007
Author(s)
Barry J. Bauer, Matthew Becker, Vardhan Bajpai, Jeffrey A. Fagan, Erik K. Hobbie, Kalman D. Migler, Charles M. Guttman, William R. Blair
The dispersion of nanotubes in solution is necessary in order to achieve the goal of sorting and manipulating nanotubes by length and type and to then prepare high quality monodisperse samples. A necessary step is the proper characterization of the

Towards Industrial Scale Fabrication of Nanowire-Based Devices

April 11, 2007
Author(s)
Babak Nikoobakht
The key requirements for mass fabrication of nanodevices are directed positioning and alignment of nanoparticles (e.g., nanowires) with known registries on a large scale. Here, these issues are addressed in a high throughput and scalable approach for

Crystallization of Polyethylene Oxide Patterend by Nanoimprint Lithography

March 28, 2007
Author(s)
Brian C. Okerberg, Christopher L. Soles, Jack F. Douglas, Hyun Wook Ro, Alamgir Karim
The crystallization behavior of poly(ethylene oxide) (PEO) films patterned by nanoimprint lithography is studied. The imprinted PEO film consists of parallel lines, approximately 240 nm wide and 320 nm tall, on a 400 nm pitch with a residual layer of
Displaying 1376 - 1400 of 1938
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