U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Jack F. Douglas (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 276 - 300 of 355

Amorphous Solidification in Polymer-Platelet Nanocomposites

December 1, 2002
Author(s)
S Salaniwal, S K. Kumar, Jack F. Douglas
Computer simulations are used to understand the molecular basis of mechanical reinforcement of platelet-filled polymers when the polymer and nanofiller interact attractively. With decreasing temperature, there is increasing aggregation between chains and

Hole Growth Instability in the Dewetting of Evaporating Polymer Solution Films

December 1, 2002
Author(s)
Xiaohong Gu, D T. Raghavan, Jack F. Douglas, Alamgir Karim
We investigate the dewetting of aqueous, evaporating polymer [poly(acrylic acid)] solutions cast on hydrophobic (polystyrene) substrates. As with typical dewetting, the evaporating films initially break up through the nucleation of holes that perforate the

Thermal and Flammability Properties of Polypropylene-Carbon Nanotube Composites

September 1, 2002
Author(s)
Takashi Kashiwagi, E A. Grulke, J N. Hilding, Richard H. Harris Jr., W H. Awad, Jack F. Douglas
Nanocomposites based on polypropylene and carbon nanotubes (up to 2 vol.-%) were melt blended, yielding good dispersion of the nanotubes without using any organic treatment or additional additives. Carbon nanotubes enhance the thermal stability of

What Do We Learn From the Local Geometry of Glass-Forming Liquids?

September 1, 2002
Author(s)
Francis W. Starr, Srikanth Sastry, Jack F. Douglas, S C. Glotzer
We examine the local geometry of a simulated glass-forming polymer melt. Using the Voronoi construction, we find that the distributions of Voronoi volume $P(v_V)$ and asphericity $P(a)$ appear to be universal properties of dense liquids, supporting the use

Bridging the Gap Between Structure and Properties in Nano-Particle Filled Polymers

July 1, 2002
Author(s)
Erik K. Hobbie, Francis W. Starr, Jack F. Douglas, Charles C. Han
On May 29-30, 2002, a workshop on polymer nanocomposites was held at NIST in Gaithersburg, Maryland. The workshop was entitled Bridging the Gap Between Structure and Properties in Nanoparticle-Filled Polymers and focused primarily on the interrelation

Growth Pulsations in Symmetric Dentritic Crystallization in Thin Polymer Blend Films

May 1, 2002
Author(s)
V Ferreiro, Jack F. Douglas, James A. Warren, Alamgir Karim
The crystallization of polymeric and metallic materials normally occurs under conditions far from equilibrium, leading to patterns that grow as propagating waves into the surrounding unstable fluid medium. The Mullins-Sekerka instability causes these wave

Shift in Polymer Blend Phase-Separation Temperature in Shear Flow

May 1, 2002
Author(s)
Jack F. Douglas
Recent experimentalstudiesof polymer blendsin simple shear flow have indicated large *Shih of the apparent phase-separation temperature. These shifts are examined within the context of a nonequilibrium hydrodynamic theory of phase separation developed by

Non-Equilibrium Pattern Formation in the Crystallization of Polymer Blend Films

April 1, 2002
Author(s)
V Ferreiro, Jack F. Douglas, James A. Warren, Alamgir Karim
The crystallization of polymeric and metallic materials normally occurs under conditions far from equilibrium. The morphologies formed reflect a competition between order associated with the symmetries of the equilibrium crystal geometry and disorder

Influence of Dendrimer Additives on the Dewetting of Thin Polystyrene Films

March 1, 2002
Author(s)
M E. Mackay, Y Hong, M Jeong, S Hong, T P. Russell, C J. Hawker, R Vestberg, Jack F. Douglas
A small mass concentration of poly(benzyl ether) dendrimer added to a low molecular mass polystyrene is found to inhibit the dewetting of a thin ( 50 nm) polystyrene film from an acid etched silicon substrate. The inhibition effect is found to depend on

A Broad Perspective on the Dynamics of Highly Confined Polymer Films

January 1, 2002
Author(s)
Christopher L. Soles, Jack F. Douglas, Wen-Li Wu, H Peng, D W. Gidley
The manner in which the dynamics of a polymer are affected by thin film confinement is of technological significance, impacting thin film applications such as lubricants, adhesives, and chemically amplified photoresists. In this manuscript we use specular

Incoherent Neutron Scattering and the Dynamics of Confined Polycarbonate Films

January 1, 2002
Author(s)
Christopher L. Soles, Jack F. Douglas, Wen-Li Wu, Robert M. Dimeo
Incoherent elastic neutron scattering measurements are performed on thin (1015 to 75 ) polycarbonate films supported on Si wafers. The mean-square atomic displacement is determined by fitting the intensity data to the Debye-Waller factor and we find that