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Search Publications by: Jack F. Douglas (Fed)

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Displaying 226 - 250 of 355

Fragility of Glass-Forming Polymer Liquids

October 4, 2005
Author(s)
J Dudowicz, Karl Freed, Jack F. Douglas
Many fluids exhibiting complex molecular structure or interactions solidify by glass-formation rather than crystallization. This tendency is especially prevalent in polymeric and biological systems where glass-formation is normal rather than exceptional

Wetting-Dewetting Transition Line in Thin Polystyrene Films

September 9, 2005
Author(s)
H Raghavan, K M. Ashley, A Seghal, Jack F. Douglas, Alamgir Karim
We review recent advances in the application of combinatorial methods to polymer thin film characterization. Combinatorial methods allow the rapid exploration of multidimensional parameter spaces that naturally arise in the description of polymer film

Exact Solution of a Field Theory Model of Frontal Photopolymerization

August 11, 2005
Author(s)
James A. Warren, J Cabral, Jack F. Douglas
Frontal photopolymerization (FPP) provides a versatile method for the rapid fabrication of solid polymer network materials by exposing photosensitive molecules to light. Dimensional control of structures created by this process is crucial in applications

Direct Measurement of the Counterion Distribution Within Swollen Polyelectrolyte Films

July 19, 2005
Author(s)
Vivek M. Prabhu, B D. Vogt, Wen-Li Wu, Eric K. Lin, Jack F. Douglas, Sushil K. Satija, D L. Goldfarb, H Ito
The depth profile of the counterion concentration within thin polyelectrolyte films was measured in situ using contrast variant specular neutron reflectivity to characterize the initial swelling stage of the film dissolution.Wefind substantial counterion

On the Growth and Form of Spherulites

July 1, 2005
Author(s)
L Granasy, T Pusztai, G -. Tegze, James A. Warren, Jack F. Douglas
Many structural materials (metal alloys, polymers, minerals, etc.) are formed by quenching liquids to form crystalline solids. This highly non-equilibrium process leads to an extraordinary variety of polycrystalline growth patterns that are broadly termed

Direct Measurement of the Counterion Distribution Within Swollen Polyelectrolyte Films

May 20, 2005
Author(s)
Vivek M. Prabhu, B D. Vogt, Wen-Li Wu, Jack F. Douglas, Eric K. Lin, Sushil K. Satija, D M. Goldfarb, H Ito
A depth profile of the counterion concentration within thin polyelectrolyte films was measured in-situ using contrast variant specular neutron reflectivity to characterize the initial swelling stage of the film dissolution. We find a substantial counterion

Interfacial Structure of Photoresist Thin Films in Developer Solutions

March 1, 2005
Author(s)
Vivek M. Prabhu, B D. Vogt, Wen-Li Wu, Jack F. Douglas, Sushil K. Satija, D M. Goldfarb, H Ito
The development step is critical to the fabrication of nanostructures in chemically amplified photoresist technology. With critical dimensions (CD) shrinking to sub-100 nm and the concurrent reduction in exposure radiation wavelength, line-edge roughness

Propagating Waves of Network Formation Induced by Light

March 1, 2005
Author(s)
J Cabral, Jack F. Douglas
The exposure of a photopolymerizable liquid to ultraviolet (UV) radiation leads to a propagating wavefront of network formation that invades the unpolymerized material from the illuminated surface of the photosensitive material. We theoretically describe

Water Immersion of Model Photoresists: Interfacial Influences on Water Concentration and Surface Morphology

February 1, 2005
Author(s)
B D. Vogt, D L. Goldfarb, M Angelopoulos, Christopher Soles, C M. Wang, Vivek Prabhu, P M. McGuiggan, Jack F. Douglas, Eric K. Lin, Wen-Li Wu, Sushil K. Satija
Immersion lithography has emerged as an alternative to the 157 nm node and as such understanding of the interactions between the photoresist and immersion fluid (water) has become a pressing issue. The water concentration within the model photoresist films

Flammability Properties of Polymer Nanocomposites with Single-Walled Carbon Nanotubes: Effects of Nanotube Dispersion and Concentration

January 1, 2005
Author(s)
Takashi Kashiwagi, F Du, K Winey, K M. Groth, John R. Shields, S Bellayer, H J. Kim, Jack F. Douglas
The effects of the dispersion and concentration of single walled carbon nanotube (SWNT) on the flammability of polymer/SWNT nanocomposites were investigated. The polymer matrix was poly (methyl lmethacrylate) (PMMA) and the SWNT were dispersed using a

Polymerization Transition in Two-Dimensional Systems of Dipolar Spheres

January 1, 2005
Author(s)
Justin Stambaugh, K VanWorkum, Jack F. Douglas, Wolfgang Losert
We investigate the self-organization of dipolar spheres into polymer chains as a fundamental model of self-assembly of particles having anisotropic interactions. Our study involves a combination of simulation and experiments on vertically vibrated magnetic

Schematic Models of Molecular Self-Organization

January 1, 2005
Author(s)
K VanWorkum, Jack F. Douglas, Wolfgang Losert
Molecular self-organization is central to the formation of numerous biological structures and the emulation of this process through the creation of synthetic counterparts offers great promise for nanofabrication. Our approach to understanding the

Extraordinary Flow Characteristics of Nanotube-Filled Polymer Materials

August 2, 2004
Author(s)
S B. Kharchenko, Kalman D. Migler, Jack F. Douglas, Jan Obrzut, E A. Grulke
Carbon nanotubes are under intense investigation due their potential for modifying the electrical conductivity (s), shear viscosity (h) and other transport properties of polymeric materials. They are hybrids of ordinary filler particles and nanoscale

Near-Field Polarimetric Characterization of Polymer Crystallites

August 1, 2004
Author(s)
Lori S. Goldner, S N. Goldie, Michael J. Fasolka, F Renaldo, Jeeseong Hwang, Jack F. Douglas
We use near-field polarimetry (NFP) to investigate thin film crystallites of isotactic polystyrene (iPS). NFP micrographs enabled quantitative optical characterization of the birefringence in these specimens with sub-diffraction limited resolution

Structural and Dynamic Heterogeneity in a Telechelic Polymer Solution

May 1, 2004
Author(s)
D Bedrov, G D. Smith, Jack F. Douglas
We utilize molecular dynamics simulations to investigate the implications of micelle formation on structural relaxation and polymer bead displacement dynamics in a model telechelic polymer solution. The transient structural heterogeneity associated with