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Search Publications by: Jack F. Douglas (Fed)

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Displaying 76 - 100 of 355

Electromagnetic Scattering from Individual Crumpled Graphene Flakes: A Characteristic Modes Approach

September 14, 2017
Author(s)
Edward J. Garboczi, Jack F. Douglas, Luis Fernando Vargas Lara, Ahmed M. Hassan, Deb Chatterjee, Kalyan Durbhakula, Md Gaffar
Graphene flakes in real composites are rarely perfectly flat, and often exhibit complicated crumpled shapes. Therefore, the goal of this work was to quantify the electromagnetic scattering characteristics of individual crumpled graphene flakes with shapes

Coarse-grained model of the dynamics of electrolyte solutions

August 17, 2017
Author(s)
Jack F. Douglas, Marat Andreev, Juan J. de Pablo, Alexandros Chremos
Ion specific solvation has fundamental implications in biochemistry and the thermo- dynamics and dynamics of aqueous salt solutions has correspondingly been investigated intensively. Nonetheless, recent works have indicated fundamental unresolved issues in

Energy renormalization approach to coarse-graining of polymer dynamics

August 8, 2017
Author(s)
Wenjie Xia, Jake Song, Cheol Jeong, David D. Hsu, Frederick R. Phelan Jr., Jack F. Douglas, Sinan Keten
A major challenge in soft matter science is the bottom-up prediction of the temperature- dependent behavior of amorphous glass-forming (GF) polymers. Coarse-grained (CG) models derived from atomistic simulation data offer chemical specificity and access to

Influence of polymer architecture on diffusion in polymers melts

August 2, 2017
Author(s)
Alexandros Chremos, Cheol Jeong, Jack F. Douglas
Recent simulations have indicated that the thermodynamic properties and the glassy dynamics of polymer melts are strongly influenced by average molecular shape, as quantified by the radius of gyration tensor of the polymer molecules, and that average

Universal Interrelation Between Measures of Particle and Polymer Size

July 6, 2017
Author(s)
Luis F. Vargas Lara, Marc L. Mansfield, Jack F. Douglas
The characterization of many objects often involves the determination of a basic set of particle size measures derived mainly from scattering and transport property measurements. For polymers, these basic properties often include the radius of gyration Rg

Dielectric Characterization of Confined Water in Chiral Cellulose Nanocrystal Films

April 10, 2017
Author(s)
Bharath N. Natarajan, Caglar Emiroglu, Jan Obrzut, Douglas M. Fox, Beatriz Pazmino, Jack F. Douglas, Jeffrey W. Gilman
A known deterrent to a large scale development and use of cellulose nanocrystals (CNCs) is their affinity for moisture, which has a profound effect on dispersion, wetting, interfacial adhesion, matrix crystallization and water uptake. To quantify the

Dynamical Heterogeneity in a Vapor-Deposited Polymer Glass

February 23, 2017
Author(s)
Jack F. Douglas, Wengang Zhang, Francis W. Starr
Recently, there has been great interest in 'ultrastable' glasses formed via vapor deposition, both because of emerging applications of these materials (e.g., active layers in light-emitting diodes and photovoltaics) and, theoretically, as materials for

Flammability Properties of PMMA-Single Walled Carbon Nanotube Nanocomposites

February 19, 2017
Author(s)
Takashi Kashiwagi, F Du, K Winey, K M. Groth, John R. Shields, Richard H. Harris Jr., Jack F. Douglas
Flammability properties of PMMA/SWNT nanocomposites were measured. The addition of SWNT significantly reduces mass loss rate of PMMA even for the contents less than a 1 % mass fraction. The dispersion of tubes affects flammability properties.

Relationship Between Quantitative Dispersion and Physical Properties of PMMA/SWNT Nanocomposites

February 19, 2017
Author(s)
Takashi Kashiwagi, Jeffrey Fagan, Keith Yamamoto, A N. Heckert, Stefan D. Leigh, Jan Obrzut, F Du, Sheng Lin-Gibson, Minfang Mu, K Winey, R Haggenmueller, Jack F. Douglas
Six PMMA/SWNT(0.5 wt%) nanocomposite samples intended to have different dispersion levels were prepared by the coagulation method using six different concentrations of SWNTs in DMF from 0.05 mg/ml to 1.2 mg/ml. The morphology of the samples was determined

Thermal Degradation and Flammability Properties of Nanocomposites

February 19, 2017
Author(s)
Takashi Kashiwagi, A B. Morgan, Joseph M. Antonucci, Richard H. Harris Jr., E A. Grulke, J N. Hilding, Jack F. Douglas
Thermal degradation and flammability properties of the two types of nanocomposites with nanosilica and carbon nanotubes were studied. PMMA, poly(metheyl methacrylate), nanocomposites were made by in situ radical polymerization of MMA, methylmethacrylate

Generalized entropy theory of glass-formation in fully flexible polymer melts

December 21, 2016
Author(s)
Jack F. Douglas, Wensheng Xu, Karl Freed
The generalized entropy theory (GET) offers many insights into how molecular parameters influence polymer glass-formation. Given the fact that chain rigidity often plays a critical role in understanding the glass- formation of polymer materials, the GET

Entropy Theory of Polymer Glass-Formation in Variable Spatial Dimension

December 20, 2016
Author(s)
Jack F. Douglas, Wensheng Xu, Karl Freed
The importance of packing frustration is broadly appreciated to be an important aspect of glass formation. Recently, great interest has focused on probing the dependence on spatial dimension d as a theoretical tool for exploring essential aspects of glass

Bound Layers Cloak Nanoparticles in Strongly Interacting Polymer Nanocomposites

December 16, 2016
Author(s)
Jack F. Douglas, Francis W. Starr, Sanat K. Kumar
Polymer-nanoparticle (NP) interfacial interactions are expected to strongly influence the properties of nanocomposites, but surprisingly, experiments often report small or no changes in the glass transition temperature, Tg. To understand this paradoxical