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Search Publications by: Jack F. Douglas (Fed)

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Displaying 201 - 225 of 355

Computer Simulations of Ionomer Self-Assembly and Dynamics

May 17, 2007
Author(s)
Moonjoy Goswami, S K. Kumar, Aniket Bhattacharya, Jack F. Douglas
Computer simulations of a model telechelic ionomer, i.e. a melt with a charge at each chain end along with neutralizing counterions, indicate a form of self-assembly that is hybrid between the packing driven interactions in block copolymers and the

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

Numerical Path-Integration Technique for the Calculation of Transport Properties

March 13, 2007
Author(s)
E Kang, M Mansfield, Jack F. Douglas
We present a new technique for the computation of both the translational diffusivity and the intrinsic viscosity of macromolecules, and apply it here to approximately 1000 different protein structures. The computed translational diffusivities and intrinsic

Crystallization-Induced Fluid Flow in Polymer Melts Undergoing Solidification

February 19, 2007
Author(s)
Donghua Xu, Z G. Wang, Jack F. Douglas
The formation of semi-crystalline plastic polymer materials often occurs under confinement conditions where high pressure imprinting or casting in a mold are involved. To gain insight into this highly non-equilibrium process, we examine the nature of the

Field-Induced Formation of Linear, Mesoscopic Polymer Chains From Ferromagnetic Nanoparticles

February 2, 2007
Author(s)
Jason Benkoski, Steven Bowles, Bryan Korth, Ronald L. Jones, Jack F. Douglas, Alamgir Karim, Jeffrey Pyun
Polymer-coated ferromagnetic colloids are first assembled with an applied magnetic field and then permanently fixed into one-dimensional mesostructures using a novel liquid-liquid interfacial system known as Fossilized Liquid Assembly. Using polystyrene

Pattern-directed to isotropic dewetting transition in polymer films on micropatterned surfaces with differential surface energy contrast

January 27, 2007
Author(s)
D Julthongpiput, Wenhua Zhang, Jack F. Douglas, Alamgir Karim, Michael J. Fasolka
Surface chemical patterns can both cause and direct dewetting in overlying thin films. However, a key factor in this behavior, the magnitude of surface energy differences between pattern domains ( ?g ), is largely unevaluated. To probe the effect of this

Photocurable Oil/Water Interfaces as a Universal Platform for 2-D Self-Assembly

December 14, 2006
Author(s)
Jason Benkoski, Ronald L. Jones, Jack F. Douglas, Alamgir Karim
We present a novel platform for the creation of 2-D assemblies from nanoscale building blocks. The system consists of an oil/water interface in which the oil phase can be flash-cured upon UV exposure. The photopolymerizable material, 1,12-dodecanediol

Characterization of Atomic Motions Governing Grain Boundary Migration

September 24, 2006
Author(s)
Hao Zhang, David J. Srolovitz, Jack F. Douglas, James A. Warren
Molecular dynamics simulations were employed to study atomic motion within stationary and migrating asymmetric tilt grain boundaries. We employ several measures of the complexity of the atomic trajectories, including the van Hove correlation function, the

A Hybrid Finite Element-Analytical Method For Determining the Intrinsic Elastic Moduli of Particles Having Moderately Extended Shapes and a Wide Rande of Elastic Properties

August 1, 2006
Author(s)
Edward J. Garboczi, Jack F. Douglas, Howard Hung
The presence of a low (dilute) concentration of paniculate inclusions having any shape and any property mismatch with the matrix in which they are placed, influences the elasticity of the resulting composite material. This influence is via the intrinsic

Polycrystalline Patterns in Far-From-Equilibrium Freezing: A Phase Field Study

August 1, 2006
Author(s)
L Granasy, T Pusztai, T Borzsonyi, G Toth, G -. Tegze, James A. Warren, Jack F. Douglas
We discuss the formation of polycrystalline microstructures with the framework of phase field theory. First, the model is tested for crystal nucleation in a hard sphere system. It is shown that, when evaluating the model parameters from molecular dynamics

Influence of Confinement on the Fragility of Antiplasticized and Pure Polymer Films

July 27, 2006
Author(s)
Robert A. Riggleman, K Yoshimoto, Jack F. Douglas, J J. de Pablo
We investigate by molecular dynamics simulation how thin film confinementmodifies the fragility of a model glass-forming liquid characterized previously in the bulk. Film confinement is found to reduce the relative fragility of the polymer fluid, leading

Symmetry, Equivalence and Molecular Self-Organization

March 1, 2006
Author(s)
K Van Workum, Jack F. Douglas
Abstract: 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

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

Lessons From Simulation Regarding the Control of Synthetic Self-Assembly

January 1, 2006
Author(s)
Jack F. Douglas, K VanWorkum
We investigate the role of the particle potential symmetry on the form of self-assembly by Monte Carlo simulation with the particular view towards synthetically creating structures of prescribed form and function. We establish a general tendency for the

Nanoparticle Networks Reduces Flammability of Polymer Nanocomposites

December 1, 2005
Author(s)
Takashi Kashiwagi, F Du, K Winey, Jack F. Douglas, Richard H. Harris Jr., John R. Shields
Synthetic polymer materials are rapidly replacing more traditional materials such as steel, nonferrous metals and natural polymeric materials. Because these novel materials are combustible under certain conditions, their utilization often requires