bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ionic Liquid Facilitated Generation of Functional Biopolymer Composite Materials
Authors: Fox Eric T , Brown Eva Kathryn , Price Tyler , Brusoski Michael , Durkin David P. , Trulove Paul C , Haverhals Luke M. , De Long Hugh C 
Published: February 2020

Ionic liquids (IL) have been the focus of materials research for some time due to their unique physical and chemical properties. Of significant interest is their ability to solubilize biopolymers such as cellulose, chitin, keratin, and silk. However, full dissolution and regeneration using IL solvents often results in biomaterials with inferior properties compared to the native material. When natural substrates are only partially dissolved and regenerated through a process called Natural Fiber Welding (NFW), much of the native biomaterial structure can be maintained while still opening up the outermost portion of fibers so that the physical and chemical properties may be manipulated and/or modified. Furthermore, if functional materials (e.g. magnetic, conductive, capacitive, antimicrobial) are present in the IL-welding solution, these materials may be entrained in and on the surface of the fiber substrate. In the present work we will discuss the spatially controlled application of the NFW process and how this can be used to generated novel conductive and capacitive structures.
Structural and Photoluminescent Characterization of Na3FMo1-X
W
x
O4
Â (0 â¤ x â¤ 1)
Authors: Sullivan Eirin Courtney 
Published: February 2020

Preliminary studies suggest that Na3FMo1-x
W
x
O4 (0 ≤ x ≤ 1) is a new family of self-activating oxyfluoride phosphors with anti-perovskite related structure [1]. These materials are isostructural with the known sodium tungsten oxyfluoride Na3FWO4 [2], as determined by Rietveld analysis based upon neutron powder diffraction data of the molybdenum-containing analogues Na3FMoO4 and Na3FW0.5Mo0.5O4. Photoluminescence studies have shown that upon excitation with λ = 254nm and λ = 365nm, the end members Na3FWO4 and Na3FMoO4 exhibit broad emission maxima centred around 485 nm and 450 nm respectively Mixed intermediates of the general formula Na3FW1-x
Mo
x
O4 have a broad absorption around λ = 350-365 nm in the near-UV region which is close to the emission from pure GaN LEDs (370 nm) thus may provide novel host lattices for new PC-LED phosphors.

References:

1. E. C. Sullivan, M. Avdeev, and T. Vogt, Manuscript in preparation.
2. I. Hartenbach and T. Schleid, Z. Anorg. Allg. Chem.,
633, 4, 524-526, 2007.

Figure 1
Electrochemical Analysis of Film Forming Mechanisms Relevant to Data Storage Chemical Mechanical Planarization
Authors: Janes Lisa M. , Keleher Jason J 
Published: February 2020

With the rapid increase of data storage density, the operation distance between read/write head and media has fallen into the nanometer regime. This requires an atomic level planarization to avoid defects on the surface and “crashes” of the read/write head media. Chemical mechanical polishing (CMP) has been selected to produce high quality surface finish on a Nickel Phosphorous (NiP) plated substrate, through the removal of a metal complex film formed on the surface. CMP is a process that balances the kinetic/ thermodynamic reactions between the formation of a chemically modified layer and its interaction with the slurry. In order to understand the mechanistic CMP film forming process, electrochemical techniques were developed to probe the impact of organic additives on the surface redox and film forming mechanisms. More specifically, through monitoring the OCP (under abrasive and nonabrasive conditions) versus time, the film removal rate and passivation film formation kinetics can be determined as a function of slurry additives. Using OCP, the film passivation of the metal slurry complex on the surface of a nickel electrode can be monitored as a function of polishing time and related to the film forming mechanism of the CMP process.
Transport and Dynamics of Ionic Species in Block Copolymer Electrolytes Obtained from NMR
Authors: Huynh Tan Vu , Messinger Robert , Bouchet Renaud , Phan Trang N. T. , Maria Sebastien , Deschamps Michaël 
Published: February 2020

Solvent-free block copolymers electrolytes are the strongest candidates for solid-state lithium metal batteries, as new polymers based on polyethylene oxide (PEO) and lithium bis(trifluoromethane)sulfonimide (LiTFSI) prevent the formation of lithium dendrites and ensure sufficient conductivity.
Block copolymers based on PEO and either polystyrene (PS) or grafted PS-TFSI were compared to PEO by Nuclear Magnetic Resonance spectroscopy (NMR) in order to quantify and distinguish the transport and dynamics of Li+ and TFSI- and the effect of the polymer matrix.
The self-diffusion coefficients of Li+ and TFSI- can be measured at various temperatures with pulsed-field-gradient (PFG) experiments and compared with electrical conductivity measurements, providing insights on lithium transport properties in each system.
We measured 7Li NMR relaxation rates at various magnetic fields and temperatures, and we were able to extract complex correlation functions describing the fluctuations of the 7Li quadrupolar interaction inside the polymer matrix, yielding insights into cation dynamics with three different timescales. These results obtained from NMR can be compared to molecular dynamics or theoretical calculations.
Electrospun Carbon Nanofiber Supports for Bioelectrodes
Authors: Do Duyen Van Thuy , Gumeci Cenk , Calabrese Barton Scott 
Published: February 2020

A high surface-area electrospun carbon nanofiber (CNF) support for bioelectrodes is introduced to enhance enzyme utilization.1 This study employed Glucose Oxidase (GOx) in redox hydrogel system, which mediated electron transfer via Osmium (Os2+/Os+) centers, to create a glucose bioelectrode. The strategy was to enhance the transport of electrons via the redox mediator by reducing the average hydrogel thickness at fixed hydrogel volume. The tunable electrospun carbon fiber enables of hydrogel film thickness of hydrogel film by uniform distribution on small fibers. Glucose oxidizing current density made from electrospun carbon nanofiber and several commercial counterparts suggest a possibility for a cheap fibers, in a diameter range below100 nm, that enable high current density (~8.5 mA cm-2) comparable to carbon nanotubes (CNTs).
To adjust electrospun CNF size, varied concentrations of Polyacrylonitrile (PAN)/ Dimethylformamide (DMF) precursor solution (7 wt% to 14 wt%) was spun in a high voltage field prior to oxidation stabilization and carbonization in Argon environment at two temperatures, 850°C and 1100°C.2 Graphiticity of CNFs was improved with the increasing heat treatment temperature (shown by Raman spectroscopy), leading to higher conductivity of bioelectrode. CNFs based on 7 wt% PAN/DMF carbonized at 1100°C had a diameter of 150 nm (Figure 1b), a decrease from the 250 nm PAN fiber (Figure 1a), and showed good performance in electrochemical characterization compared to MWCNTs electrode (Figure 2).

Acknowledgement

We thank Buckeye Composites Inc. and Pyrograf Products Inc. for providing material samples.

Reference

(1) Wen, H.; Nallathambi, V.; Chakraborty, D.; Calabrese Barton, S. Carbon Fiber Microelectrodes Modified with Carbon Nanotubes as a New Support for Immobilization of Glucose Oxidase. Microchim. Acta
2011, 175, 283–289.
(2) Bhardwaj, N.; Kundu, S. C. Electrospinning: A Fascinating Fiber Fabrication Technique. Biotechnol. Adv.
2010, 28, 325–347.

Figure 1
(Dielectric Science & Technology Division Thomas D. Callinan Award) Boron Carbon Nitride Thin Films for Low-k Dielectric Interconnect and Optical Applications
Authors: Sundaram Kalpathy B , Prakash Adithya , King Sean W. 
Published: February 2020

New microprocessor CMOS technologies require interlayer dielectric materials with lower dielectric constant than those used in current technologies to meet RC delay goals and to minimize cross-talk. Silicon oxide or fluorinated silicon oxide (SiOF) materials having dielectric constant in the range of 3.6 to 4 have been used for many technology nodes. In order to meet the aggressive RC delay goals, new technologies require dielectric materials with k < 3. Boron carbide nitride (BCN) shows promise as a low dielectric constant material with good mechanical strength suitable to be used in newer CMOS technologies. BCN ternary system exhibits exceptional properties and attract much attention from mechanical, optical and electronic perspectives. BCN thin films contain interesting phases such as diamond, cubic BN (c-BN), hexagonal boron nitride (h-BN), B4C, β-C3N4. Attempts have been made to form a material with semiconducting properties between the semi metallic graphite and the insulating h-BN, or to combine the cubic phases of diamond and c-BN (BC2N heterodiamond) in order to merge the higher hardness of the diamond with the advantages of c-BN, in particular with its better chemical resistance to iron and oxygen at elevated temperatures.
For optical applications, the deposition of BCN coatings on polymers is a promising method for protecting the polymer surface against wear and scratching. BCN films have high optical transparency and thus can be used as mask substrates for X-ray lithography.
In this work, the deposition and characterization of amorphous thin films of boron carbon nitride (BCN) are reported. The BCN thin films were deposited by radio frequency (rf) magnetron sputtering technique. The BCN films were deposited by sputtering from a high purity B4C target with the incorporation of nitrogen gas in the sputtering ambient. Films of different compositions were deposited by varying the ratios of argon and nitrogen in the sputtering ambient. Investigation of the oxidation kinetics of these materials was performed to study high temperature compatibility of the material. Both the dielectric and optical properties seem to be sensitive to carbon and nitrogen content in the films.
Exploration of Ammonia Production in Blue Green Algae By Bioelectrocatalytic Methods
Authors: Lyon Jacob , Paschkewitz Timothy , Leddy Johna 
Published: February 2020

Ammonia is an important compound to many industries around the world. Most of the fertilizers used by crop growers have ammonia as an essential ingredient. It can also be useful as a fuel source, offering greater energy density per unit than hydrogen, and greater safety. Currently, the predominant method for producing ammonia on an industrial scale is by the Haber-Bosch process. This process uses steam evolution of methane to provide H2 gas, which is then combined with N2 gas over an iron catalyst to form NH3. This process requires large amounts of energy as well as high temperatures and pressures.
In this report, an alternative method for ammonia production is explored. With Anabaena Variabilis, a photosynthetic cyanobacteria, on a carbon electrode, ammonia can be generated at ambient temperatures and pressures at little energy cost, a few tenths of a volt.1,2 A bioelectrocatalytic device has been constructed by immobilizing whole cell a. variabilis in a Nafion film modified with a trimethyl octadecyl ammonium bromide (TMODA) salt at an electrode surface.3 The ammonium salt enlarges the pore size of the Nafion structure while neutralizing the acidic environment of the polymer, and provides a hospitable matrix for the algae cells. The polymer modified electrode provides the driving force and reductive microenvironment to facilitate production of NH3 by nitrogenase and nitrate/nitrite reductase enzymes present in a. variabilis. Ammonia production by cyanobacteria was increased from basal levels of 2.8 ± 0.4 µM produced over a two week period, to 22 ± 8 µM produced in 20 minutes under mild voltage perturbation, a roughly 104 increase in rate. Control of ammonia producing structures (nitrogenase or nitrate/nitrite reductase) can be accomplished by growing the algae with and without fixed sources of nitrogen in the growth media. The addition of nitrates and nitrites to the electrolyte during voltammetric perturbation varies linearly with ammonia increased with substrate.
References:
[1] Johna Leddy and Timothy M. Pashkewitz, Ammonia Production Using Bioelectrocatalytic Devices, US Patent Application 20140011252.
[2] Timothy M. Paschkewitz. Ammonia Production at Ambient Temperature and Pressure: An Electrochemical and Biological Approach. Ph.D. dissertation. University of Iowa, 2012.
[3] Tamar L. Klotzbach; Michelle Watt; Yasmin Ansari; Shelley D. Minteer. Improving the microenvironment for enzyme immobilization at electrodes by hydrophobically modifying chitosan and Nafion polymers.Journal of Membrane Science, 311, 1-2, 20 March 2008, 81-88.
Bio-Electrochemical Systems in the Subalpine Lake Idro (Italy)
Authors: Cristiani Pierangela 
Published: February 2020

The subalpine Lake Idro in the north of Italy is here described from a physico-chemical and electrochemical point of view. The glacial origin of the lake, together with the steep walls of the basin and the maximum depth of 120 m, creates the conditions for the evolution of a stable meromictic condition during the year. The presence of a superficial layer of aerobic water (a mixolimion of about 50 m) and of a deep constant layer under anaerobiosis (monimolimion) makes it a unique environment for electrochemical studies. A peculiarity of this lake is the presence of a cloudy white layer at the chemocline, detected at 40-60 m of depth by scuba divers and never reported in literature. The hydrographic basin is mostly composed of dolomite, the typical rock of the Alps. The general chemical composition is Mg(Ca)CO3, but it could include impurities such as Fe and Mn.
Many are the peculiarities converging to produce a unique environment for Mn cycling in the mixolimion, chemocline, and monimolimion characterizing the lake. On the basis of home-built sensors and a standard multiparametric probe, oxygen, pH, sulphide, conductivity, red-ox and temperature profiles were determined. Strict correlations were found between these parameters and the different oxidation states of Mn (Mn+2, Mn+3 and Mn+4) detected in the water and in the particulate. Equilibria with Fe and other elements have been considered.
A chain of copper alloy (CuNi 70/30) and carbon steel was immersed at different depths in the water down to the bottom of the lake, in a point where the lake depth is the maximum (120 m), to study electrochemical and biological characteristics of the lake. Unique correlations between the chemical-physical parameters and electrochemical characteristics of copper alloys specimens, exposed at different depth in the lake, were demonstrated. The open circuit potential of copper alloys, measured versus the same Ag/AgCl reference electrode used for the sulphide measurements, varied as a function of the oxygen concentration in the different water layers and stabilized in time in each layer (from +200 mV down to -600 mV vs. Ag/AgCl). The results indicated that, in different ways, handmade sensors can be cost effective tools, able to give insight into the redox conditions of water.
The stratification of the lake poses a new interesting studies for MFCs. In this environment, microbial fuel cells (MFC) might produce power by utilizing the microbial capacity of catalyzing the oxygen reduction at the cathode, and the Mn(OH)2 oxidation at the anode. Another type of MFC might develop power by reduction of Mn2O3.
The natural scenario of the Lake Idro suggests studies of new bio-electrochemical technologies that could be applied for environment-depollution purposes.
Pd-Based Metal Aerogels with Promoted Bioelectrocatalytic Behavior
Authors: Wen Dan , Liu Wei , Eychmüller Alexander 
Published: February 2020

Aerogels derived from noble metal nanoparticles (NPs) are a new kind of metal materials, which combine the nano-sized scale with that of materials of macro dimensions.[1] These metal aerogels are expected to provide a matrix with high electrical conductivity and high surface area for electrochemical applications. They may also offer inherent catalytic activity and generally fast (reversible) electron-transfer kinetics. In that respect, enzyme-loaded metallic aerogels in combination with their meso/macroporous structure can facilitate electron and mass transfer processes, which are both important for bioelectronic applications, e.g., in electrochemical biosensors and in biofuel cells.[2]
Here the controlled growth of Pd aerogels has been facilely realized by using calcium ions as the destabilizing agent. The involving Pd aerogels with different porosities and surface areas exhibited faster electrode kinetics and higher activities towards the bioelectrooxidation of glucose when co-immobilized with glucose oxidase (GOD), compared to the Pd NPs and glassy carbon.[3] Based on the Pd aerogels promoted bioelectrocatalysis, we have developed a newly designed metal aerogel-based biofuel cell system. In the text, a commonly used mediator, ferrocenecarboxylic acid (Fc), was integrated into the Pd hydrogel and thus produced a Pd-Fc composite aerogel mediator for GOD at the bioanode. Additionally, bilirubin oxidase (BOD) encapsulated into a Pd-Pt alloy aerogel played a synergetic role towards the reduction of O2, which promoted the direct electrocatalytic reduction of O2 at the biocathode with an onset potential of 0.56 V under neutral conditions. By employing these two bioelectrodes, the assembled membrane-less glucose/O2 biofuel cell showed a maximum power output of 20 μW cm-2 at 0.25 V.[4,5]
References
[1] N. Gaponik, A.-K. Herrmann, A. Eychmüller, J. Phys.
Chem. Lett.
2012, 3, 8–17.
[2] Gao, F.; Viry, L.; Maugey, M.; Poulin, P.; Mano, N. Nat.
Commun.
2010, 1, 2.
[3] D. Wen, A.-K. Herrmann, L. Borchardt, F. Simon, W. Liu, S. Kaskel, A. Eychmüller, J. Am.
Chem. Soc.
2014, 136, 2727–2730.
[4] W. Liu, P. Rodriguez, L. Borchardt, A. Foelske, J. Yuan, A.-K. Herrmann, D. Geiger, Z. Zheng, S. Kaskel, N. Gaponik, R. Kötz, T. Schmidt, A. Eychmüller, Angew.
Chem., Int. Ed.
2013, 52, 9849–9852.
[5] D. Wen, W. Liu, A.-K. Herrmann, A. Eychmüller, Chem. Eur. J.
2014, 20, 4380–4385.

Figure 1
Stochastic Sensors Based on Diamond Paste for Screening of Biological Fluids for Neurotransmitters
Authors: Stefan-van Staden Raluca-Ioana , Moldoveanu Iuliana , VAN Staden Jacobus Frederick 
Published: February 2020

Diamond paste proved to be one of the best matrices for the design of stochastic sensors. Therefore, different porhyrins were immobilized in diamond paste.
The “signatures” of neurotransmitters were determined. The “signatures” were used to identify these analytes on the diagrams obtained when whole blood was screened. Quantitative analysis was also performed using these microsensors. The results obtained using the proposed microsensors were correlating very well with those obtained using the standard methods used in clinical analysis.
Acknowledgements The present work was supported by the European Commission through the DENAMIC project (Contract-No. 282957) and by UEFISCDI, Romania Contract-no. 186/23.10.2012.
Thermal Properties of Chemically Modified Carbon Nanotubes Dispersed in Polymer Matrices
Authors: Januszko Adam W , Peszke Jerzy , Pawlicka Agnieszka , Czujko Tomasz 
Published: February 2020

Keywords: carbon nanotubes, polymer, functional composite, thermal properties of functional composite.
A functional composite (FC) was obtained by mixing polymers from the group of polyacrylic acid ester derivatives and polymethylacrylate, copolymers of polyvinyl alcohol (PVA), polyurethanes, ethoxylate derivatives of silicones and chemically functionalized multiwall carbon nanotubes (FMCN). The result was a subject of temperature dependence measurement on electrical resistivity, as well as mechanical strength and flexibility. FC has presented durable, flexible properties and demonstrated a resistance in the range of 20 - 40 Ω. A silicone composite has presented a best chemical and physical properties in broad range of temperature (up to 100°C). Thermal images were studied using infrared (IR) camera and characterized by histograms. The morphology of the functional composites have been observed by SEM and discussed.
The work also presents number of methods of nanostructures preparation, which are the most commonly used.
(Invited) Photoluminescence Carrier Dynamics and Photon Statistics of Covalent Dopant-Induced Trap States in Single Wall Carbon Nanotubes
Authors: Doorn Stephen K. , Ma Xuedan , Hartmann Nicolai F. , Yalcin Sibel E. , Htoon Han 
Published: February 2020

Recent advances in low level covalent functionalization of carbon nanotubes are receiving significant attention due to new emitting states being introduced by chemically stable oxygen1,2 and aryl diazonium dopants3 that increase photoluminescence quantum yields. Recent low-temperature studies have further elucidated the associated chemical and electronic structure.4 We report here photoluminescence studies of dynamic behaviors of the dopant sites. Relevant to their potential uses in imaging and as novel photon sources, we demonstrate blinking behaviors and discuss a range of response as a function of dopant species. We also report across a range of dopants photoluminescence decay dynamics obtained at the ensemble and single tube levels. We find that localization of excitons at dopant sites dramatically increases photoluminescence lifetimes, indicating the importance of exciton trapping as a route to limiting non-radiative decay pathways arising from exciton mobility. Relevant to interest in these new emitting states as single photon emitters for quantum information processing, we also demonstrate an approach to stabilizing emission output while also introducing solitary dopant sites. Finally, lifetime and photon correlation studies enabled by superconducting nanowire single-photon detectors will be presented. Evolution of behaviors as a function of temperature will be discussed in the context of realizing room-temperature photon antibunching.
1. S. Ghosh, et al., Science, 330, 1656 (2010).
2. Y. Piao, et al., Nature Chem., 5, 840 (2013).
3. Y. Miyauchi, et al., Nature Photon., 7, 715 (2013).
4. X. Ma, et al., ACS Nano, 8, 10782 (2014).
Anchoring Semiconductor and Metal Nanoparticle on Graphene Oxide for Simultaneous Sensing and Degradation of Contaminants
Authors: Kamat Prashant V , Alam Rabeka 
Published: February 2020

Manipulation of photoinduced charge transfer processes on a graphene based catalyst mat has allowed us to tailor the properties for photocatalytic and sensing applications. We have deposited luminescent CdSe quantum dots and SERS active silver nanoparticles to introduce photocatalytic and sensing properties. The role of the GO sheet is to establish electronic communication between semiconductor and metal NPs and promote adsorption of molecules near the silver nanoparticle surface. The GO-assisted communication between semiconductor and metal NPs in particular has enabled us to enhance the detection limit for low level nitroaromatic compounds in water. For example, CdSe emission is quenched upon adsorption of nitrobenzene. Following excitation with visible light the reduction of nitro group to amine proceeds at the CdSe surface and restores the emission. Thus the multifunctional hybrid assemblies designed in this study enable us to achieve greater detection sensitivity as well as capability to degrade the organic contaminants from water.