Author Archives: Teh Chen Mary Walsh

Center for Neutron Science at the University of Delaware: Neutron Metrology for Solving Grand Challenge Problems by Engineering the Tools of Scientific Discovery

This cooperative agreement between the Center for Neutron Science (CNS) at the University of Delaware (UD) and the NCNR for the purpose of advancing neutron scattering metrology for research and by using this neutron science to address the following NAE Grand Challenge Problems: Engineering Better Medicines, Restore and Improve Urban Infrastructure, and Engineering the Tools of Scientific Discovery.

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Norman Wagner

Engineer, inventor, mentor named 2020 Francis Alison winner

Wagner’s lifelong curiosity and delight in science, research and collaborative problem-solving have fueled an inventive career that has inspired many a colleague and student, drawn international recognition and now is distinguished with the University of Delaware’s highest faculty honor — the 2020 Francis Alison Award. The award, established in 1978, is named for the University’s founder, the Rev. Francis Alison, and recognizes contributions and distinction as both a scholar and an educator.

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A team of engineers has shown that surface diffusion in protein transport into ion-exchange beads depends on adsorption affinity — a measure of attraction between the two materials.

UD engineers uncover role of surface diffusion in protein transport, which could aid biopharmaceutical processing

A team of engineers from the University of Delaware, with a collaborator from pharmaceutical company Amgen, has shown that surface diffusion in protein transport into ion-exchange beads depends on adsorption affinity — a measure of attraction between the two materials. By exploiting this relationship, the team developed a procedure to purify a monoclonal antibody — a type of molecule that mediates immunity — with productivity 43% higher than usual.

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Center for Neutron Science team wins $11M grant from NSF

Senator Chris Coons congratulates University of Delaware’s Norm Wagner and Center for Neutron Science Team

Senator Chris Coons: “Congrats to @UDelaware’s Norm Wagner & his Center for Neutron Science team for winning an $11M grant from @NSF. This funding will help American scientists, NIST, UD, UMD & partners close an important gap by supporting both research & the best neutron measurement instrumentation.”

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Understanding Gas Storage in Cuboctahedral Porous Coordination Cages

Bloch Group recently published a paper in JACS where neutron diffraction was used to study methane binding sites in porous materials

Gregory R. Lorzing, Eric J. Gosselin, Benjamin A. Trump, Arthur H. P. York, Arni Sturluson, Casey A. Rowland, Glenn P. A. Yap, Craig M. Brown, Cory M. Simon, Eric D. Bloch*

Porous molecular solids are promising materials for gas storage and gas separation applications. However, given the relative dearth of structural information concerning these materials, additional studies are vital for further understanding their properties and developing design parameters for their optimization. Here, we examine a series of isostructural cuboctahedral, paddlewheel-based coordination cages, M24(tBu-bdc)24 (M = Cr, Mo, Ru; tBu-bdc2– = 5-tert-butylisophthalate), for high-pressure methane storage. As the decrease in crystallinity upon activation of these porous molecular materials precludes diffraction studies, we turn to a related class of pillared coordination cage-based metal–organic frameworks, M24(Me-bdc)24(dabco)6 (M = Fe, Co; Me-bdc2– = 5-methylisophthalate; dabco = 1,4-diazabicyclo[2.2.2]octane) for neutron diffraction studies. The five porous materials display BET surface areas from 1057–1937 m2/g and total methane uptake capacities of up to 143 cm3(STP)/cm3. Both the porous cages and cage-based frameworks display methane adsorption enthalpies of −15 to −22 kJ/mol. Also supported by molecular modeling, neutron diffraction studies indicate that the triangular windows of the cage are favorable methane adsorption sites with CD4–arene interactions between 3.7 and 4.1 Å. At both low and high loadings, two additional methane adsorption sites on the exterior surface of the cage are apparent for a total of 56 adsorption sites per cage. These results show that M24L24 cages are competent gas storage materials and further adsorption sites may be optimized by judicious ligand functionalization to control extracage pore space.

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Protection Using STF-Armor™ and Self-Healing Polymers

University of Delaware/NASA Johnson Space Center, Human Exploration & Operations, Space Technology Mission Directorates, International Space Station

The low-Earth orbit (LEO) environment exposes astronauts performing extravehicular activity (EVA) to potential threats from micrometeoroid and orbital debris (MMOD). Moreover, impacts of MMOD with the International Space Station (ISS) can cause craters along hand railings which can pose a cutting threat to astronauts during EVA missions. In this research, we are developing advanced nanocomposite textiles based on STF-Armor™ to improve astronaut survivability. The aim of these investigations is the incorporation of the STF technology to improve the protection of astronaut EPGs capable of withstanding extended exposure to the space environment during multiple EVAs. A hypodermic needle puncture test is used to simulate the threat posed by damaged surfaces. LEO-compatible-STF-treated spacesuit layups are two times more resistant to puncture than the current TMG, without sacrificing weight and thickness of the spacesuit. The longevity and robustness of LEO-STF-treated spacesuit materials, successfully launched with the Materials International Space Station Experiments, MISSE-9, aboard SpaceX-14 resupply mission on April 2, 2018, will be tested over the next year. The samples will be exposed to extreme levels of solar and charged-particle radiation, atomic oxygen, hard vacuum, and temperature extremes. The gathered data including monthly high-resolution images of the samples, temperature, particulate contamination and UV intensity data can be used to evaluate the proposed LEO-STF spacesuit materials for possible use in planetary exploration beyond Earth such as NASA’s mission to Mars. Industry Collaboration: STF Technologies, LLC and Alpha Space Test and Research Alliance, LLC

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Cathy Wu, Craig Brown and Anderson Janotti

Cathy Wu, Craig Brown and Anderson Janotti make list of top influencers

Engineers at the University of Delaware do research that garners attention from scientists and engineers around the world, and three faculty members in the College of Engineering were recently named to the Clarivate Analytics list of Highly Cited Researchers for 2018. This list identifies scholars whose publications are in the top 1% for citations by other researchers via Web of Science, a scientific citation indexing service. Researchers can be cited for top performance in their field or for Cross-Field impact, a new category this year. Read on for more about UD engineering’s highly cited academics.

Craig M. Brown is a staff chemist at the National Institute of Standards and Technology (NIST) center for Neutron Research and an adjunct professor through UD’s Center for Neutron Science, which was founded in 2007. Under a cooperative agreement with NIST, UD’s Center for Neutron Science advances the field of neutron scattering by developing new techniques, applying these techniques to new applications, and training the next generation of neutron scientists. Brown, who studies the structure and dynamics of novel materials, made the 2018 Highly Cited Researchers list in the Cross-Field category. Among his most cited works are papers on molecular adsorption for energy efficient industrial separations, and hydrogen storage in materials, which hold promise in applications for cleaner energy and automotive technology. Brown has published more than 175 peer-reviewed papers, which have garnered more than 12,000 citations. His work has an h-index of 50, and an i10-index of 144 based on Google Scholar.

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Methane Storage in Paddlewheel-Based Porous Coordination Cages

Casey A. Rowland, Gregory R. Lorzing, Eric J. Gosselin, Benjamin A. Trump, Glenn P. A. Yap, Craig M. Brown, and Eric D. Bloch
J. Am. Chem. Soc.
DOI: 10.1021/jacs.8b05780
Publication Date (Web): August 18, 2018
Copyright © 2018 American Chemical Society

Although gas adsorption properties of extended three-dimensional metal-organic materials have been widely studied, they remain relatively unexplored in porous molecular systems. This is particularly the case for porous coordination cages for which surface areas are typically not reported. Herein, we report the synthesis, characterization, activation, and gas adsorption properties of a family of carbazole-based cages. The chromium analog displays a coordination cage record BET surface area of 1235 m2/g. With precise synthesis and activation procedures, two previously reported cages similarly display high surface areas. The materials exhibit high methane adsorption capacities at 65 bar with the chromium(II) cage displaying CH4 capacities of 194 cm3/g and 148 cm3/cm3. This high uptake is a result of optimal pore design, which was confirmed via powder neutron diffraction experiments.

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Branching and Alignment in Reverse Worm-like Micelles Studied with Simultaneous Dielectric Spectroscopy and RheoSANS†

John K. Riley, Jeffrey J. Richards, Norman J. Wagner and Paul D. Butler
rsc.li/soft-matter-journal
Volume 14 | Number 26 | 14 July 2018 | Pages 5335–5538
ISSN 1744-6848 | DOI: 10.1039/c8sm00770e

Topology and branching play an important but poorly understood role in controlling the mechanical and flow properties of worm-like micelles (WLMs). To address the challenge of characterizing branching during flow of WLMs, dielectric spectroscopy, rheology, and small-angle neutron scattering (dielectric RheoSANS) experiments are performed simultaneously to measure the concurrent evolution of conductivity, permittivity, stress, and segmental anisotropy of reverse WLMs under steady-shear flow. Reverse WLMs are microemulsions comprised of the phospholipid surfactant lecithin dispersed in oil with water solubilized in the micelle core. Their electrical properties are independently sensitive to the WLM topology and dynamics. To isolate the effects of branching, dielectric RheoSANS is performed on WLMs in n-decane, which show fast breakage times and exhibit a continuous branching transition for water-to-surfactant ratios above the corresponding maximum in zero-shear viscosity. The unbranched WLMs in n-decane exhibit only subtle decreases in their electrical properties under flow that are driven by chain alignment and structural anisotropy in the plane perpendicular to the electric field and incident neutron beam. These results are in qualitative agreement with additional measurements on a purely linear WLM system in cyclohexane despite differences in breakage kinetics and a stronger tendency for the latter to shear band. In contrast, the branched micelles in n-decane (higher water content) undergo non-monotonic changes in permittivity and more pronounced decreases in conductivity under flow. The combined steady-shear electrical and microstructural measurements are capable, for the first time, of resolving branch breaking at low shear rates prior to alignment-driven anisotropy at higher shear rates.

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Gas Adsorption in an Isostructural Series of Pillared Coordination Cages

Eric J. Gosselin, Gregory R. Lorzing, Benjamin A. Trump, Craig M. Brown and Eric D. Bloch
ChemComm
Issue 49, 2018
Department of Chemistry & Biochemistry, University of Delaware, Newark, USA
E-mail: edb@udel.edu
Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware
Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, USA

The synthesis and characterization of two novel pillared coordination cages is reported. By utilizing 1,4-diazabicyclo[2.2.2]octane (dabco) as a pillar with increased basicity as compared to pyrazine or 4,4′-bipyridine, a stable copper-based material was prepared. Extending this strategy to iron(II) afforded an isostructural material that similarly retains high porosity and crystallinity upon solvent evacuation. Importantly, the iron solid represents a rare example of porous iron paddlewheel-based metal–organic material that is stable to solvent evacuation. Neutron powder diffraction studies on these materials indicate the triangular and square windows of the cage are prime ethane and ethylene adsorption sites.