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Displaying 351 - 375 of 1930

Flow fluctuations in wormlike micelle fluids

October 22, 2018
Author(s)
Paul NMN Salipante, Steven Meek, Steven D Hudson
We investigate the unstable flow of wormlike micelle solutions in pressure driven capillary flow, with a focus on the effect of entrance geometry on the fluid fluctuations. The flow is measured at different points in the capillary using particle image

Combinatorial Cassettes for Higher-Throughput Screening of Osteogenesis

October 4, 2018
Author(s)
Carl G. Simon Jr., Subhadip Bodhak, Hariharan K. Iyer, Luis Fernandez de Castro Diaz, Pam Robey, Azusa Maeda, Sergei Kuznetsov
Animal models are the most biologically relevant method for measuring the osteogenic capability of bone graft formulations. However, animal experiments are slow, tedious and the results can be highly variable, even when conducted within the same lab. In

Advancing the computational methodology of rigid rod and semiflexible polymer systems: A new solution to the wormlike chain model with rod-coil copolymer calculations

October 3, 2018
Author(s)
Adam F. Hannon, Regis J. Kline, Dean DeLongchamp
A wormlike chain model for rod type blocks in a rod‐coil diblock copolymer is implemented in the self‐consistent field theory (SCFT) formalism. A pseudo‐spectral method is used to solve for the single‐chain partition function of this copolymer system

Evaluation of Degradation Models for High Strength p-Aramid Fibres Used in Body Armour

October 1, 2018
Author(s)
Kirk D. Rice, Amy E. Engelbrecht-Wiggans, Emilien J. Guigues, Amanda Forster
To improve the reliability and design of armour, it is imperative to understand the failure modes and the degradation rates of the materials used in armour. Despite the best efforts of manufacturers, some vulnerability of armour materials to ageing due

On the mechanisms and the characterization of the pulsed electron grafting of styrene onto poly(tetrafluoroethylene-co-hexafluoropropylene) to synthesize a polymer electrolyte membrane

September 21, 2018
Author(s)
Byung N. Kim, Alia Weaver, Marina Chumakov, Ileana M. Pazos, Dianne L. Poster, Karen Gaskell, Do H. Han, Gunther Scherer, Michael A. Yandrasits, Byung C. Lee, Mohamad Al-Sheikhly
During the pulsed-electron beam direct grafting of neat styrene onto poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) substrate, the radiolytically-produced styryl and carbon-centered FEP radicals undergo various desired and undesired competing

Fundamentals and characterizations of scratch resistance on automotive clearcoats

September 11, 2018
Author(s)
Li Piin Sung, Linqian Feng, Nadia Benhamida, Pierre Morel, Andrew T. Detwiler, Jon M. Skelly, Leslie T. Baker, Deepanjan Bhattacharya
As original equipment manufacturers (OEMs) strive to deliver improved coating performance with a sustainable footprint, opportunities for innovation are emerging, particularly on improving mechanical properties, appearance, and solids content. Resistance

Flow-induced crystallization during materials extrusion additive manufacturing

September 10, 2018
Author(s)
Lily Northcutt, Sara Orski, Kalman D. Migler, Anthony Kotula
Material extrusion additive manufacturing processes force molten polymer through a printer nozzle at high (> 100 s-1) wall shear rates prior to cooling and crystallization. These high shear rates can lead to flow-induced crystallization in common polymer

Protocols for Determining the Mechanical Properties of High Strength Copolymer Aramid Fibers

September 1, 2018
Author(s)
Amanda L. Forster, Viviana Rodriguez Cardenas, Ajay Krishnamurthy, Amy E. Engelbrecht-Wiggans, Zois Tsinas
The primary goal of the manuscript is to develop a protocol to prepare consistent specimens for accurate mechanical testing of high strength copolymer aramid fibers, by removing a coating and disentangling the individual fiber strands without introducing

SEIRAS Study of Chloride Mediated Polyether Adsorption on Cu

August 31, 2018
Author(s)
Thomas P. Moffat, Daniel Josell, Lee J. Richter
Surface enhanced infrared absorption spectroscopy (SEIRAS) was used to examine the co- adsorption of a selection of polyethers with Cl- under conditions relevant to superconformal Cu electrodeposition in CuSO4-H2SO4 electrolytes. In 0.1 mol/L H2SO4 a

A Readily Programmable, Fully Reversible Shape Switching Material

August 24, 2018
Author(s)
Matthew McBride, Alina Martinez, Lewis M. Cox, Marvin Alim, Kimberly Childress, Michael Beiswinger, Maciej Podgorski, Brady Worrell, Jason Killgore, Christopher N. Bowman
Liquid crystalline elastomers (LCEs) enable large scale reversible shape changes in polymeric materials; however, they require intensive, irreversible programming approaches to facilitate controllable actuation. We have implemented photo-induced dynamic

Complex coacervation in polyelectrolytes from a coarse-grained model

August 22, 2018
Author(s)
Vivek M. Prabhu, Marat Andreev, Jian Qin, Matthew Tirrell, Juan J. de Pablo, Jack F. Douglas
Polyelectrolyte coacervation refers to the formation of distinct liquid phases that arise when polyelectrolytes of opposite charge are mixed under appropriate polymer and salt concentrations. Molecular-level studies of complex polyelectrolyte coacervation

Competitive solvation effects in polyelectrolyte solutions

August 1, 2018
Author(s)
Alexandros Chremos, Jack F. Douglas
An understanding of the solution properties and phase behavior of natural and synthetic polyelectrolytes requires an understanding of the competitive association of water (“hydration”) and ion association to the polymer backbone and the consequences of

Aggregation and Solubility of a Model Conjugated Donor-Acceptor Polymer

July 31, 2018
Author(s)
Daniel R. Reid, Nicholas E. Jackson, Alexander J. Bourque, Chad R. Snyder, Ronald L. Jones, Juan de Pablo
In organic semiconductors, solution-phase polymer structure and aggregation have a strong influence on device morphology and performance. Thus, understanding solubility of conjugated polymers is crucial for their rational design. Using a combination of

Effect of temperature on the structure and dynamics of triblock copolymer coacervate hydrogels

July 16, 2018
Author(s)
Vivek M. Prabhu, Ryan C. Nieuwendaal, Anand Rahalkar, Juan J. DePablo, Samanvaya Srivastava, Matthew Tirrell
Triblock copolymer coacervate gels were characterized by small-angle neutron scattering (SANS) and dynamic light scattering. The oppositely charged polyelectrolyte complex core size does not change with temperature. However, the neutral middle block that

Characterization of Interfacial Structure in Polymer-Fullerene Bulk Heterojunctions via 13C {2H} Rotational Echo Double Resonance NMR

July 13, 2018
Author(s)
Ryan C. Nieuwendaal, Dean M. DeLongchamp, Martin Heeney, Jan Hummelen, Chad R. Snyder, Ronald L. Jones, Sebastian Engmann, Lee J. Richter, Zhuping Fei, Alex Sieval
We introduce a new application of solid state NMR measurements towards characterizing the donor-acceptor interfaces within bulk heterojunction (BHJ) films. Rotational echo double resonance (REDOR) is used to measure dipolar couplings between 13C nuclei on
Displaying 351 - 375 of 1930
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