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 151 - 175 of 1922

Interface History on Strain Field Evolution in Epoxy Resins

January 21, 2022
Author(s)
Edward Garboczi, Newell Moser, Jena McCollum, Jared Strutton, Abby Jennings, Brandon Runnels
To determine the viability of digital image correlation in the analysis of additively manufactured thermosets, we devised a testing method to examine the effect of interface history (i.e., time between interface formation and original material deposition)

Predicting the plateau modulus from molecular parameters of conjugated polymers

January 18, 2022
Author(s)
Abigail Fenton, Renxuan Xie, Melissa Aplan, Youngmin Lee, Michael Gill, Ryan Fair, Fabian Kempe, Michael Sommer, Chad R. Snyder, Enrique Gomez, Ralph Colby
The relationship between Kuhn length lk, Kuhn monomer volume v0, and plateau modulus GN0 , initially proposed by Graessley and Edwards for flexible polymers, and extended by Everaers, has a large gap in experimental data between the flexible and stiff

Non-fullerene acceptors with direct and indirect hexa-fluorination afford > 17% efficiency in polymer solar cells

December 22, 2021
Author(s)
Subhrangsu Mukherjee, Guoping Li, Liang-Wen Feng, Leighton Jones, Robert Jacobberger, Wei Huang, Ryan Young, Robert Pankow, Weigang Zhu, Norman Lu, Kevin Kohlstedt, Vinod Sangwan, Michael Wasielewski, Mark Hersam, George Schatz, Dean DeLongchamp, Antonio Facchetti, Tobin Marks
The rational molecular design of non-fullerene acceptors (NFAs) in organic solar cells (OSCs) can profoundly influence the photovoltaic (OPV) performance. To date, NFA fluorination has proven beneficial to cell performance. However, there is a lack of

Orientation of Thin Polyamide Layer-by-Layer Films on Non-Porous Substrates

December 16, 2021
Author(s)
Tawanda J. Zimudzi, Sarah E. Sheffield, Kathleen E. Feldman, Peter Beaucage, Dean DeLongchamp, Douglas I. Kushner, Christopher Stafford, Michael A. Hickner
The orientation of polyamide thin films on non-porous substrates was investigated using Fourier transform infrared (FTIR) spectroscopy and corroborated by near edge X-ray absorption fine structure (NEXAFS) measurements. Polyamide films comprised of m

Thermal Shrinkage Reveals the Feasibility of Pulse-delay Photocuring Technique

December 1, 2021
Author(s)
Sri Vikram Palagummi, Taeseung Hong, Li Jiang, Martin Chiang
Objectives: To resolve applicability of the pulse-delay photocuring technique to restorative dental composites as a clinical strategy for the reduction in the detrimental polymerization stress. Methods: Model dental composites with high and low-filler

Systematically Controlling Acceptor Fluorination Optimizes Hierarchical Morphology, Vertical Phase Separation, and Efficiency in Non-Fullerene Organic Solar Cells

November 21, 2021
Author(s)
Guoping Li, Xiaohua Zhang, Subhrangsu Mukherjee, Wei Huang, Ding Zheng, Liang-Wen Feng, Yao Chen, Jianglin Wu, Vinod Sangwan, Mark Hersam, Dean DeLongchamp, Junsheng Yu, Antonio Facchetti, Tobin Marks
Non-fullerene acceptor (NFA) end group (EG) functionalization, especially by fluorination, affects not only the energetics but also the morphology of bulk-heterojunction (BHJ) organic solar cell (OSC) active layers, thereby influencing the power conversion

Activation of Mechanophores in a Thermoset Matrix by Instrumented Scratch

November 17, 2021
Author(s)
Chelsea S. Davis, Jeremiah Woodcock, Ryan Beams, Mitchell Rencheck, Muzhou Wang, Stephan J. Stranick, Aaron M. Forster, Jeffrey Gilman
Scratches in polymer coatings and barrier layers negatively impact optical properties (haze, light transmission, etc.), initiate routes of degradation or corrosion (moisture permeability), and nucleate delamination of the coating. Detecting scratches in

Solvent-cast 3D Printing of Biodegradable Polymer Scaffolds

October 22, 2021
Author(s)
John Tolbert, Diana Hammerstone, Nathaniel Yuchimiuk, Jonathan Seppala, Lesley Chow
Three-dimensional (3D) printing is a popular technique to fabricate scaffolds for tissue engineering because of its ability to produce complex tissue-like architectures. Scaffolds are often 3D printed using biodegradable polymers like poly(caprolactone)

Imperfect Surface Order and Functionalization in Vertical Carbon Nanotube Arrays Probed by Near Edge X-ray Absorption Fine Structure Spectroscoy (NEXAFS)

October 12, 2021
Author(s)
T Hemraj-Benny, S Banerjee, S Sambasivan, Daniel A. Fischer, G Eres, Alexander Puretzky, David B. Geohegan, D H. Lowndes, J A. Misewich, S S. Wong
Probing surface order in nanotube systems is of fundamental importance for incorporation of these materials into practical electronic devices. The current study pertains to analysis of the surface orientation of vertically aligned single-walled and multi

Measuring Tie Chains and Trapped Entanglements in Semicrystalline Polymers

September 21, 2021
Author(s)
Amanda G. McDermott, Paul DesLauriers, Jeff Fodor, Ronald L. Jones, Chad R. Snyder
A label-free method for quantifying stress-transmitter (or elastically effective molecule) content (p) in semicrystalline polymers, including both tie molecules and bridging entanglements, is developed and demonstrated based on swelling with deuterated

Side Chain Engineering Control of Mixed Conduction in Oligoethylene Glycol-Substituted Polythiophenes

August 31, 2021
Author(s)
Jonathan Onorato, Zhongyang Wang, Yangyang Sun, Christian Nowak, Ban Dong, Lucas Flagg, Ruipeng Li, Lee J. Richter, Fernando Escobedo, Paul Nealey, Shrayesh Patel, Christine Luscombe
A major limitation for polymeric mixed ionic/electronic conductors (MIECs) is the trade-off between ionic and electronic conductivity; changes made that improve one typically hinder the other. In order to address this fundamental problem, this work

Polarized X-ray scattering measures molecular orientation in polymer-grafted nanoparticles

August 12, 2021
Author(s)
Subhrangsu Mukherjee, Dean DeLongchamp, Eliot Gann, Daniel Sunday, Lee Richter, Jason Streit, Richard A. Vaia, Baskar Ganapathysubramanian, Kumar Saurabh, Adarsh Krishnamurthy
Polymer chains are attached to nanoparticle surfaces for many purposes, including altering solubility, influencing aggregation, dispersion, and even tailoring immune responses in drug delivery. The most unique structural motif of polymer-grafted

Temperature-insensitive silicone composites as ballistic witness materials: the impact of water content on the thermophysical properties

July 28, 2021
Author(s)
Ran Tao, Fan Zhang, Huong Giang Nguyen, Philip Bernstein, Amanda L. Forster, Randy Mrozek, Aaron M. Forster
In this work, different formulations of a room-temperature silicone composite backing material (SCBM) composed of polydimethylsiloxane (PDMS), fumed silica and corn starch were investigated using different characterization techniques, i.e., differential

Simulated filament shapes in embedded 3D printing

July 22, 2021
Author(s)
Leanne Friedrich, Jonathan Seppala
Embedded 3D printing, wherein fluid inks are extruded into a bath, has enabled the manufacture of complex, custom structures ranging from cell-laden tissue analogues to soft robotics. This method encompasses two techniques: embedded ink writing (EIW)

Fluorescence Microscopy Reveals Structure-Property Relationships and Polymer Dynamics in Biocomposites

July 21, 2021
Author(s)
Quinn Easter, Shawn Chen, Jeremiah Woodcock, Amanda Souna, Sindhu Seethamraju, Jan Obrzut, Douglas M. Fox, Stephan J. Stranick, Jeffrey Gilman
OBJECTIVES: Developing the next generation of materials for use in restorative work requires a multifaceted approach. While mimicking the properties of the tooth, currently available dental composites and porcelains eventually fail and require replacement

Supersonic Impact Response of Polymer Thin Films via Large-Scale Atomistic Simulations

July 15, 2021
Author(s)
Andrew L. Bowman, Edwin Chan, William B. Lawrimore, John K. Newman
Recent nanoscale ballistic testing studies have shown the applicability of nanomaterials for ballistic protection but have raised new questions regarding the nanoscale structure-property relationships that contribute to the enhanced ballistic response of

Molecular Mass Dependence of Interfacial Tension in Complex Coacervation

June 11, 2021
Author(s)
Debra Audus, Samim Ali, Artem Rumyantsev, Yuanchi Ma, Juan J. de Pablo, Vivek Prabhu
The interfacial tension of coacervates, the liquidlike phase composed of oppositely charged polymers that coexists at equilibrium with a supernatant, forms the basis for multiple technologies. Here we present a comprehensive set of experiments and

Buried Structure in Block Copolymer Films Revealed by Soft X-ray Reflectivity

May 20, 2021
Author(s)
Daniel Sunday, Jacob L. Thelen, Regis Kline, Chun Zhou, Jiaxing Ren, Paul Nealey
Interactions between polymers and surfaces can be used to influence properties including mechanical performance in nanocomposites, the glass transition temperature, and the orientation of thin film block copolymers (BCPs). In this work we investigate how
Displaying 151 - 175 of 1922
Was this page helpful?