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Search Publications by: Jack F. Douglas (Fed)

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Displaying 301 - 325 of 355

Phase Separation in Ultrathin Polymer Films

January 1, 2002
Author(s)
Alamgir Karim, Jack F. Douglas, Li Piin Sung, B D. Ermi
Changes in phase separation morphology occurring in thin polymer blend films is discussed. These changes are especially large when the films are thinner than the scale of the bulk material interfacial profile width. Under these circumstances, phase

Intrinsic Viscosity and the Electric Polarizability of Arbitrarily Shaped Objects

December 1, 2001
Author(s)
M Mansfield, Jack F. Douglas, Edward Garboczi
The problem of calculating the electrical polarizability tensor αe of objects of arbitrary shape has been reformulated in terms of path integration and implemented computationally. The method simultaneously yields the electrostatic capacity C and the

Gelation in Physically Associating Polymer Solutions

October 1, 2001
Author(s)
S K. Kumar, Jack F. Douglas
The thermally reversible gelation of a polymer solution is investigated. The dynamics slows down upon cooling in these systems much like glass-firming liquids. We show that no significant changes in the dynamics occurs near the geometrical percolation

High Throughput Approach to Crystallization in Thin Films of Isotactic Polystyrene

August 1, 2001
Author(s)
Kathryn L. Beers, Jack F. Douglas, Eric J. Amis, Alamgir Karim
The dependence of the crystallization rate of isotactic polystyrene was measured as a function of film thickness and temperature on films with continuous gradients. The results agreed with literature values obtained on discrete films. This validates the

Studies of polymer-filler interactions in filled systems

August 1, 2001
Author(s)
Alamgir Karim, Jack F. Douglas, K A. Barnes, A Nakatani, D W. Liu, Eric J. Amis
We observe that the presence of filler partiocles can have a major impact on the properties of filled polymer blend materials. The filler particles, which are found in many commercial polymer blends, modify the phase boundary (interfacial tension, rate of

Combinatoral Study of Surface Pattern Formation in Thin Block Copolymer Films

July 1, 2001
Author(s)
A P. Smith, Jack F. Douglas, Alamgir Karim, J C. Meredith, Eric J. Amis
We investigate surface patterns in thin block copolymer films with a gradient in thickness, h. The usual hole and island morphologies are found when h varies from integral multiples m of the bulk lamellar thickness Lo but spinodal-like hole and island

Combinatorial Study of Surface Pattern Formation in Thin Block Copolymer Films

July 1, 2001
Author(s)
A P. Smith, Jack F. Douglas, J C. Meredith, Eric J. Amis, Alamgir Karim
Surface pattern formation in thin diblock copolymer films is investigated utilizing a high-throughput methodology to validate the combinatorial measurement approach for polymer science. Measurement libraries of block copolymer films having gradients in

Thermodynamic Regulation of Actin Polymerization

June 1, 2001
Author(s)
P S. Niranjan, J G. Forbes, S C. Greer, J Dudowicz, Karl Freed, Jack F. Douglas
A Flory-Huggins-type lattice model of actin polymerization under equilibrium conditions is employed to analyze new spectroscopic measurements for the extent of actin polymerization diameter} as a function of temperature T, salt concentration [KC1], and the

Characterization of Symmetric Diblock Copolymers With High-Throughput Techniques

April 1, 2001
Author(s)
Alamgir Karim, A P. Smith, Jack F. Douglas, Eric J. Amis
Surface pattern formation in thin block copolymer films is investigated utilizing a high-throughput methodology by creating films having gradients in film thickness. We observe a succession of surface patterns that repeat cyclically across the film with

Critical Properties and Phase Separation in Lattice Boltzmann Fluid Mixtures

March 1, 2001
Author(s)
Nicos Martys, Jack F. Douglas
Basic equilibrium properties of Lattice Boltzmann (LB) fluid mixtures (coexistence curve, surface tension, interfacial profile, correlation length) are calculated to characterize the critical phenomena occurring in these model liquids and to establish a

Crystallization of Isotactic Polystyrene in Thin Films: A High Throughput Approach

January 1, 2001
Author(s)
Kathryn L. Beers, Jack F. Douglas, Eric J. Amis, Alamgir Karim
Very thin films of semi-crystalline polymers are increasingly being employed in coatings applications and there is a need to better understand how film thickness and crystallization conditions influence the crystalline morphology and resultingfilm