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Search Publications

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Displaying 351 - 375 of 1719

Evolution of Dendrimer Conformational Structure with Generation Number

June 20, 2016
Author(s)
Beatriz A. Pazmino, Jack F. Douglas
We simulate the conformational structure of a coarse-grained model of dendrimer molecules in good solvent as a function of generation number G and find that they evolve through a substantially more complex structures than regular star polymer with

How to measure absolute P3HT crystallinity via 13C CPMAS NMR

April 20, 2016
Author(s)
Ryan C Nieuwendaal
We outline the details of acquiring quantitative 13C cross-polarization magic angle spinning (CPMAS) NMR spectra on the most ubiquitous polymer for organic electronics (OE) applications, poly(3-hexylthiophene) (P3HT), despite other groups’ claims that

Structural control of mixed ionic and electronic transport in conducting polymers

April 17, 2016
Author(s)
Jonathan Rivnay, Sahika Inal, Brian Collins, Michelle Sessolo, Eleni Stavrindou, Christopher Tassone, Dean DeLongchamp, George Malliaras
Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate), PEDOT:PSS, has been utilized for over two decades as a stable, solution-processable conductor. While electrical properties have been the subject of intense materials investigation, recent

Super Stiff and Highly Transparent Multilayer Thin Films Prepared through Hydrogen-Bonding Layer- by-Layer Assembly of Graphene and Polymer

February 8, 2016
Author(s)
Fangming Xiang, Dorsa Parviz, Tara M. Givens, Ping Tzeng, Eric Davis, Christopher Stafford, Micah J. Green, Jaime C. Grunlan
Since its discovery in 2004, graphene has been intensely studied due to its high elastic modulus, thermal conductivity, electrical conductivity, and gas impermeability. Although it is possible to use small quantities of graphene sheets for fundamental

Morphological origins of polarization-induced scattering anisotropy from organic thin films

January 14, 2016
Author(s)
Eliot Gann, Brian A. Collins, Maolong Tang, John R. Tumbleston, Subhrangsu Mukherjee, Harald W. Ade
Anisotropic scattering patterns have been observed from organic thin films that are isotropic on the scale of the probe in polarized resonant X-ray scattering experiments. The symmetry is broken by local correlations between molecular orientation and

ASTM Workshop on Standards & Measurements for Tissue Engineering Scaffolds

January 1, 2016
Author(s)
Carl G. Simon Jr., John Test, Michael Yaszemski, Reto Luginbuehl, Anthony Ratcliffe, Paul Tomlins
A “Workshop on Standards & Measurements for Tissue Engineering Scaffolds” was held on May 21, 2013 and was sponsored by the American Society of Testing and Materials International (ASTM International) in Indianapolis, IN. The purpose of the workshop was to

The Occurrence of Repeated Fiber Breaks in Microcomposites

November 10, 2015
Author(s)
Gale A. Holmes, Edward D. McCarthy, Nathanael A. Heckert, Stefan D. Leigh, Jae Hyun Kim, Jeffrey W. Gilman
The mechanical integrity of a structural composite is strongly affected by the strength and toughness of the fiber–matrix interface/interphase (Norwood, 1994), with interfacial shear strength (IFSS) considered the best quantifying metric. IFSS outputs are

Structural origins of enhanced capacity retention in novel copolymerized sulfur-based composite cathodes for high-energy density Li-S batteries

September 17, 2015
Author(s)
Vladimir P. Oleshko, Jenny J. Kim, Jennifer L. Schaefer, Steven D. Hudson, Christopher L. Soles, Adam Simmonds, Jared Griebel, Kookheon Char, Jeff Pyun
Poly(sulfur-random-(1,3-diisopropenylbenzene) (poly(S-r-DIB)) copolymers synthesized via inverse vulcanization form high molecular mass electrochemically active polymers capable of realizing enhanced capacity retention (1005 mAh/g at 100 cycles) and

SYNTHESIS AND PROPERTIES OF THERMOPLASTIC POLYURETHANES WITH ISOSORBIDE CHAIN EXTENDER

August 28, 2015
Author(s)
Fan Zhang, Ivan Javni, Olivera Bili?, Nikola Bili? , Zoran S. Petrovic, Jan Ilavsky
Isosorbide, a renewable diol derived from starch, was used in combination with butane diol or alone as the chain extender in two series of thermoplastic polyurethanes with 50 and 70% soft segment concentration (SSC). Polyurethanes with 50% SSC based on

In-Situ Method for Measuring the Mechanical Properties of Nafion Thin Films during Hydration Cycles

August 15, 2015
Author(s)
Kirt A. Page, Jae W. Shin, Scott Eastman, Brandon W. Rowe, Sangcheol Kim, Ahmet Kusoglu, Kevin G. Yager, Gery R. Stafford
Perfluorinated ionomers, in particular Nafion, are an essential component in hydrogen fuel cells, as both the proton exchange membrane and the binder within the catalyst layer. During normal operation of a hydrogen fuel cell the ionomer will progressively

Field-based simulations of nanostructured polyelectrolyte gels

August 11, 2015
Author(s)
Debra J. Audus, Glenn Fredrickson
Nanostructured, responsive hydrogels composed of oppositely charged triblock copolymers with charged end-blocks and neutral, hydrophilic mid-blocks in aqueous solution were recently discovered. Due to electrostatic interactions, the end-blocks microphase

Heterogeneity and length scale effects in PEG-based hydrogels

August 10, 2015
Author(s)
Brian G. Bush, Jenna M. Shapiro, Frank W. DelRio, Robert F. Cook, Michelle L. Oyen
Colloidal-probe spherical indentation load-relaxation experiments are conducted on poly(ethylene glycol) (PEG) hydrogel materials to quantify the steady-state mechanical properties and time-dependent transport properties in a single experiment. A probe

Diff use interface methods for modeling drug eluting stent coatings

July 17, 2015
Author(s)
James A. Warren, David Saylor, Christopher Forrey, Changsoo Kim
An overview of diff use interface models specific to drug eluting stent coatings is presented. Microscale heterogeneities, both in the coating and use environment, dictate the performance of these coatings. Using diffuse interface methods, these

The evolution of carbon nanotube network structure in unidirectional nanocomposites resolved by quantitative electron tomography

June 23, 2015
Author(s)
Bharath NMN Natarajan, Noa Lachman, Thomas F. Lam, Douglas Jacobs, Christian J. Long, Minhua Zhao, Brian L. Wardle, Renu Sharma, James A. Liddle
Carbon nanotube (CNT) reinforced polymers are next-generation, high-performance, multifunctional materials with a wide array of promising applications. The successful introduction of such materials is hampered by the lack of a quantitative understanding of

Mesomorphic Pathway in Early Stage Crystallization of Polyethylene

June 18, 2015
Author(s)
Kalman D. Migler, Angela R. Hight Walker, Anthony P. Kotula
The kinetic pathway by which a molten polymer transforms into a multi-length scale semi-crystalline structure upon cooling is an unsolved problem in polymer physics, yet it is critical to the processing, properties and ultimate performance of these

Small-Angle X-ray Scattering of Ionic Liquids

June 1, 2015
Author(s)
Fan Zhang, Joshua A. Hammons, Jan Ilavsky
Small angle X-ray scattering (SAXS) is a powerful technique that is used to resolve the size and structure of phases on the nanometer scale, within a sample. While these features may also be observed with other techniques, such as: electron microscopy or
Displaying 351 - 375 of 1719