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

NIST Authors in Bold

Displaying 1176 - 1200 of 1856

Diffusion-controlled, self-organized growth of symmetric wrinkling patterns

March 1, 2009
Author(s)
Jun Y. Chung, Adam J. Nolte, Christopher Stafford
Nature is particularly adept at creating ordered patterns ranging from the wind-shaped ripples on a sand dune to spiral patterns found in sea shells or galaxies. Scientists have been striving to design systems with the same level of richness and complexity

Semiconducting Thienothiophene Copolymers: Design, Synthesis, Morphology and Performance in Thin Film Organic Transistors

March 1, 2009
Author(s)
Iain McCulloch, Martin Heeney, Michael L. Chabinyc, Dean DeLongchamp, Regis J. Kline, Michael Colle, Warren Duffy, Daniel A. Fischer, David J. Gundlach, Behrang Hamadani, Rick Hamilton, Lee J. Richter, Alberto Salleo, Martin Shkunov, David Sparrowe, Steve Tierney, Weimin Zhang
Organic semiconductors are emerging as a viable alternative to amorphous silicon in a range of thin film transistor devices. , With the possibility to formulate these p-type materials as inks and subsequently print into patterned devices, organic based

A parametric interatomic potential for graphene

February 27, 2009
Author(s)
Vinod K. Tewary, B. Yang
A parametric interatomic potential is constructed for graphene. The potential energy consists of two parts: bond energy and radial interaction energy. The bond energy part is a generalized version of the Tersoff-Brenner potential. It includes angular terms

Evaluation of Polydimethylsiloxane Modification Methods for Cell Response

February 20, 2009
Author(s)
Lisa Pakstis, Alan Zheng, Theodore V. Vorburger, Joy P. Dunkers, Timothy P. Quinn, Marcus T. Cicerone
Many methods exist in the literature to modify surfaces with extracellular matrix (ECM) proteins prior to cell attachment. However, there are few studies that systematically compare surface characterization and cell response results among different

The molecular basis of mesophase ordering in a thiophene-based copolymer

February 18, 2009
Author(s)
Dean M. DeLongchamp, Regis J. Kline, Youngsuk Jung, Eric K. Lin, Daniel A. Fischer, David J. Gundlach, Andrew Moad, Lee J. Richter, Michael F. Toney, Martin Heeney, Iain McCulloch
The carrier mobility of poly(2,5-bis(3-alkylthiophen-2-yl) thieno[3,2-b]thiophene) semiconductors can be substantially enhanced after heating through a thermotropic mesophase transition, which causes a significant improvement in thin film structural order

Adhesion at layer-by-layer surfaces in aqueous environments

February 15, 2009
Author(s)
Adam J. Nolte, Jun Y. Chung, Marlon L. Walker, Christopher M. Stafford
Adhesion between materials is often governed by the ambient environment, which can mediate or change the types of molecular interactions present at an interface. Biological interactions, for example, can be mediated by factors such as temperature, ionic

Subsurface Patterning and its Effect on Interfacial Adhesion

February 15, 2009
Author(s)
Edwin P. Chan, Christopher M. Stafford
Nature (e.g. geckos and insects) has illustrated that a patterned surface can effectively tailor the adhesion of an interface. Inspired by the amazing attachment and detachment ability of these animals, significant efforts have been put forth to understand

Ultrathin Adhesives: Confinement Effect on Modulus

February 15, 2009
Author(s)
Jessica M. Torres, Christopher Stafford, Bryan D. Vogt
In this work, we will employ this wrinkling metrology to extract the modulus of polymer thin films for a homologous series of poly(n-alkyl methacrylate)s. In particular, we take advantage of the decrease in Tg as the alkyl chain length increases for these

Predicting Failure in Mammalian Enamel

January 16, 2009
Author(s)
Brian R. Lawn, James J. Lee, Paul Constantino, Peter Lucas
Dentition is a vital element of human and animal function, yet there is little fundamental knowledge about how tooth enamel endures under stringent oral conditions. This paper describes a novel approach to the issue. Model glass dome specimens fabricated

Living Anionic Polymerization Using a Microfluidic Reactor

January 15, 2009
Author(s)
Thomas Q. Chastek, Kazunori Iida, Eric J. Amis, Michael J. Fasolka, Kathryn L. Beers, Jae H. Chun
Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 °C) and high monomer concentration (42 %, by

Impact of Polymer Chemistry on the Durability of Model Adhesives Supported on SiOx Substrates in Humid Environments Using Homologous Series of Poly(n-alkyl methacrylate)s

January 7, 2009
Author(s)
Kar T. Tan, Bryan D. Vogt, Christopher C. White, Kristen Hamilton, Nicholas Wagman, Joshua E. Goldman, Jessica M. Torres, Kristen L. Steffens, Cyril Clerici, Sushil K. Satija, Donald L. Hunston
There are many advantages that structural adhesives can offer compared to the more traditional joining methods, such as welding, bolting, mechanical fastening, etc. However, there are some issues that currently limit the wider application of adhesives. One

In-situ Adhesion Measurements Utilizing Layer-by-layer Functionalized Surfaces

January 7, 2009
Author(s)
Adam J. Nolte, Jun Y. Chung, Marlon L. Walker, Christopher Stafford
The adhesion between poly(dimethylsiloxane) (PDMS) hemispheres coated with layer-by-layer (LbL) assemblies of polyelectrolytes was investigated using Johnson, Kendall, and Roberts (JKR) contact mechanics. Measurements were performed against amine

Adhesive bonding to dentin improved by polymerizable cyclodextrin derivatives

January 5, 2009
Author(s)
Rafael L. Bowen, Gary E. Schumacher, Anthony A. Giuseppetti, Kathleen M. Flynn, Charles M. Guttman, Clifton M. Carey
Objectives. Determine bonding characteristics of a hydrophilic monomer formulation containing PCDs (Polymerizable Cyclodextrin Derivatives). The hypothesis was that a formulation containing hydrophilic cross-linking diluent comonomers and PCD molecules

Particle Motion During the Compaction of Granular Matter

December 19, 2008
Author(s)
Steven Slotterback, Masahiro Toiya, Leonard Goff, Jack F. Douglas, Wolfgang Losert
We track particle motions in a granular material subjected to compaction using a laser scattering based imaging method where compaction is achieved through thermal cycling. Particle displacements in this jammed fluid correlate strongly with rearrangments

Elastic Modulus of Faceted Aluminum Nitride Nanotubes Measured by Contact Resonance Atomic Force Microscopy

December 17, 2008
Author(s)
Gheorghe Stan, C Ciobanu, Timothy Thayer, George Wang, Randall Creighton, Premsagar P. Kavuri, Leonid A. Bendersky, Robert F. Cook
A new methodology for determining the radial elastic modulus of a one-dimensional nanostructure laid on a substrate has been developed. The methodology consists of the combination of contact resonance atomic force microscopy (AFM) with finite element

Technique for Monitoring Environmentally Induced Changes in Polymeric Sealants

December 17, 2008
Author(s)
Donald L. Hunston, Kar T. Tan, Christopher C. White
A new procedure was developed to utilize stress relaxation tests to monitor damage induced in sealant materials exposed to environmental variables and changing strains. By combining tension and compression tests, it was possible to monitor both molecular
Displaying 1176 - 1200 of 1856