bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-Dimensional Bi-Continuous Graphene Monolith from Hollow Ni Templates Via Polymer Templates
Authors: Zhu Yu 
Published: February 2020

The stack of graphene sheets greatly reduces its exceptionally high specific surface area, which limits the potential utilization of graphene. Here in this work, we report a method to fabricate three-dimensional, bi-continuous graphene monolith through a controllable hollow Ni templates derived from polymer blends. The poly(styrene)/poly (ethylene oxide) were used to fabricate a bi-continuous gyroid template with controllable phase separation. The nickel template was formed by electroless depositing metal on the polymer and the resulting hollow nickel structure exhibited very high porosity of 95.15%. Graphene was synthesized from this hollow nickel template by chemical vapor deposition and the free-standing bi-continuous graphene monolith was obtained in high throughput. The bi-continuous graphene monolith was used in the energy storage devices and exhibited promising results.

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Highly Active Nitrogen-Doped Carbon Metal Oxide Hybrid Composites for Oxygen Reduction Reaction
Authors: Bayati Maryam , Scott Keith 
Published: February 2020

Fuel Cells have been considered as clean and promising energy-converting devices due to their high efficiency and low/ zero emission. However, the cost and reliability are two challenges for their commercialization. The high cost of components, which is mainly due to the use of platinum-based catalysts for oxygen reduction reaction (ORR), is attracted extensive research works on finding alternatives synthesized from low-cost and more abundant compounds.
Recent studies on pyrolyzed metal inserted nitrogen doped carbon based catalysts for ORR show high performance, at level of platinum-based catalyst, and promising durability. Herein, we report synthesis, characterization and electrochemical analysis of hybrid composites consisting of N-doped (predominantly pyridinic N- and pyrrolic) carbons and transition metal (cobalt and iron) oxides for the ORR. XPS and XRD studies revealed the active nitrogen groups and crystallographic phases of nanoparticles. The composite catalysts were prepared via a solvothermal pyrolysis process. They exhibit high catalytic activity with the 4e or 2e reaction pathways and superior stability to Pt/C for ORR in alkaline media.

Figure 1. Cyclic voltammograms of hybrid composite of iron oxide inserted N-doped carbon nanomaterials in O2-saturated solution of 0.1 M NaOH at 20 ±2 °C under different rotation rates.( Sweep rate = 10 mVs-1)

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(Plenary) Wearable Wireless Textile Based Nanosensor System for Early Detection of Concussion and Cardiac Arrest of Football Players
Authors: Varadan Vijay K 
Published: February 2020

The prevalence of head injury and its subsequent effects among football players has been a persistent problem at all levels of the game. Research work over the past few decades has brought heightened awareness about the causes and long-term effects of severe or traumatic head injuries (TBI) and repeated concussions. The NFL and NCAA have implemented policies for prevention and protocols for diagnosis and treatment. An injury surveillance system is in place, which comprises of injury spotting, sideline evaluation protocol and subsequent diagnostic using brain imaging. But mild and moderate head injuries can still occur and go undetected. The cumulative effect of these mild traumatic brain injuries can cause long-term residual brain dysfunctions. Often mild TBI are detected upon manifestation of these dysfunctions.
Improvement in impact detection and quantification, and injury diagnosis are required for timely medical intervention to prevent or minimize the damage due to head injury. In addition to that, a sensitive (neuro) feedback system is required for evaluation of therapeutics used for enabling players returning to play or cope with long term effects due to over-exposure to head injury. This requires a continuous unobtrusive monitoring of directional and rotational impact force, and monitoring of brain, cognitive and behavioral symptoms that is applicable to athletes of all ages.
The sudden death of an individual resulting from a sudden failure in heart function is referred to as Sudden Cardiac Death (SCD). Rigorous exercise increases the risk of SCDs in young athletes with underlying cardiovascular disorders (CVD). A recent study has shown that up to 82% of individuals who succumbed to SCD were engaged in strenuous exercise during or immediately before the incident. Nearly 58% of SCDs reported between 1980 and 2006 have been reported in basketball and football athletes.
In this talk, a wearable wireless textile based nanosensor system will be presented to monitor early warning symptoms of both concussion and cardiac arrest. Selected videos will be presented to show the efficacy of our nanosensor system network.
(Invited) Microneedle Array Features in Precise Moulding of Biocompatible Polymers
Authors: Ito Hiroshi , Taki Kentaro , Takayama Tetsuo , Uchiumi Kazuyasu , Yahagi Haruki 
Published: February 2020

Microneedle array features were fabricated by micro-injection molding using biocompatible polymers such as polycarbonate (PC), polypropylene (PP) and polylacticacid (PLA). PC and PP based microneedle array features with high aspect ratio for needle height was fabricated by several injection molding techniques. Injection compression molding and injection molding with super critical carbon dioxide fluid with or without vacuum process inside the cavity of mold were performed. Effects of process parameters on processability and surface replication of the molded parts were evaluated. The height replication ratio for micro-needle was improved by using injection compression molding. Moreover, the effect of vacuum process inside cavity of mold under filling process was small. However the height replication ratio for micro-needle showed the highest values using the injection molding with super critical carbon dioxide fluid with vacuum inside the cavity of mold process. In addition, hydroxyapatite (HAp) particle dispersed PLA composites based microneedle array features were also fabricated by twin screw extrusion and micro-injection molding. The viscosity of PLA was reduced by HAp dispersion because of acceleration of hydrolysis degradation during both processing. The micro-needle array of HAp/PLA composites for application to biomedical parts was obtained and the needle height was improved by the optimum composition of HAp to polymer.
Thiol-Sensitive Electrochemical Sensors for Advance Detection of Neurotoxins in Water and Biomass
Authors: Pilip Anna , Eremenko Arcadij , Kurochkin Ilijya , Russkikh Iana , Prokopkina Taisiya 
Published: February 2020

A method for the analysis of thiocholine, as well as of butyrylcholinesterase (BChE) and its inhibitors using thiol-sensitive thick-film sensors has been proposed. Sensor sensitivity to thiocholine was achieved by mediator layer of manganese dioxide formed on the working carbon electrode. The detection limit for BChE and its inhibitor diazinon was 1·10-10 M and 1·10-9 M, respectively.
The developed method of analysis using a thiol-sensitive sensor chip was applied for rapid determination of anticholinesterase substances in natural waters and to control the incoming water mass at water intakes. In this case, the analysis was carried out on a "common" neurotoxicity, which may be the cause of unauthorized releases of relevant toxins or harmful blue-green algae. Studies of natural reservoirs show seasonal changes "common" neurotoxicity, which generally confirmed by biological observations.
As a verification method for the analysis of natural water samples contained cyanotoxins and showed the presence of a "common neurotoxicity" the absence of phosphorus-organic and carbamate compounds of anthropogenic origin (pesticides, for example) also confirmed using high - performance liquid – chromatography – high-resolution -mass - spectrometry (HPLC-HRMS) (LTQ Orbitrap, Thermo Finnigan).
Combinatorial Structures of Graphene Oxide and SnO2 for Sensing various VOCs
Authors: Park Hyejin , Chung Yoonsung , Lee Eunji , Ahn Soohyun , Lee Seokhee , Ahn Hosang , KIM Dong-Joo 
Published: February 2020

Graphene (GR) and reduced graphene oxide (r-GO) are outstanding candidates for gas-sensing elements due to extremely high surface-to-volume ratio and excellent electrical properties [1]. Their unique and attractive properties can lead to novel sensors with minimum power consumption, room temperature sensing, and sensitivity. But limitations of slow reaction speed and recovery rate of the GR based sensors were observed [2]. The addition of metal oxide to make combinatorial structures with GR is being exploited as a potential way to overcome such limits
The nanostructured metal oxides such as zinc oxide (ZnO) and tin oxide (SnO2) have been demonstrated as gas sensing materials with excellent semiconducting properties [3]. However, gas sensing of the metal oxide typically requires elevated temperatures, which causes energy consumption, and limits wide range of applications. Combination of GR/r-GO and metal oxide, especially SnO2, may present potential benefits by reducing energy consumption and enhancing response rate. Several approaches were attempted to make this combinatorial structure for gas sensing, but the approaches were mostly to utilize good electrical properties of r-GO. Few studies were conducted in applying non-treated graphene oxide (GO) for gas sensing. Since multilayer of GO has been demonstrated as good semiconducting materials [4], systematic approach to combine non-treated GO and metal oxide with changing the ratio as well as their combinatorial structures on gas sensing behaviors are investigated in this study.
Combinatorial structures of GO and SnO2 were fabricated via electrophoretic deposition (EPD). The hierarchical oxide nanostructure of GO and SnO2 was analyzed by SEM and XRD as shown in Fig. 1. Mixture ratio was adjusted by adding different amount of SnO2 nanoparticles, and its effect on gas sensing behaviors was investigated. Fig. 2 shows the gas sensing behaviors of the GO/SnO2 composite films with 100 ppm of formaldehyde gas (HCHO). Gas sensing performance with non-treated GO and GO/SnO2mixture were demonstrated at room temperature. The strategies to construct combinatorial structure and their sensing behaviors in conjunction with sensing mechanisms are discussed in detail.
This research was partially supported by a grant from a Strategic Research Project (2013-0132) funded by the Korea Institute of Construction Technology, and Auburn University IGP.
[1] Lu, G., Ocola, L. E., & Chen, J. Applied Physics Letters, 94(8), 083111. (2009).
[2] Dreyer, D. R., Park, S., Bielawski, C. W., & Ruoff, R. S. Chemical Society Reviews, 39(1), 228-240. (2010).
[3] Park, H., Ahn, H., Chung, Y., Cho, S. B., Yoon, Y. S., & Kim, D. J. Materials Letters, 136, 164-167. (2014).
[4] Wang, C., Yin, L., Zhang, L., Xiang, D., & Gao, R. 10(3), 2088-2106. (2010).

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Photochemical Decoration of Metal/Metal-Oxide Nanoparticles on SnO2 Nanorods for Improved Hybrid Gas Sensors and Photodetectors for Environmental Applications
Authors: Carvajal Christian G , Kadri Killani , Rutherford Gugu , Pradhan Aswini K 
Published: February 2020

Highly oriented SnO2 nanorods were grown on different substrates by using the Vapor-Liquid-Solid (VLS) technique. The nanorods films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX). Photochemical nanoparticle decoration using a UV radiation source of 254nm wavelength was carried out to generate dispersed metallic (Au & Ag) and metal-oxide (CuO & NiO) nanoparticles attached on separated samples. The pre-decoration precursor solutions were prepared at same morality ratio and were used for chemical bath decoration at same irradiation time. The resulting hybrid transducer properties will be extensively discussed.
Chemical sensing properties of the as-prepared hybrid films demonstrated high selectivity gas detection response to CO, H2S, C2H6O and C3H6O. Light sensitivity properties have been characterized as well; a significant increased photocurrent in response to UV radiation was observed. The devise processing and experimental measurement parameters will be described and preliminary results will be presented.
This work is supported by NSF-CREST organization.
Studies on Carbon Mediated Paste Screen Printed Sensors for Blood Glucose Sensing Application
Authors: K Varadharaj Eswaramoorthy , Jampana Nagaraju 
Published: February 2020

Ready to use screen printed glucose sensors are fabricated using Prussian Blue (PB) and Cobalt PhthaloCyanine (CoPC) mediated carbon paste as working electrodes. The reference and counter electrodes are screen printed using silver/silver chloride and graphitic carbon paste respectively. The stability of screen printed reference electrode (SPRE) is examined with standard calomel electrode and found to be stable for more than 60 minutes. Optimal operating voltage for PB and CoPC screen printed sensors as determined by hydrodynamic voltammetric technique are 0.3 V and -0.1 V respectively. The sensing response of fabricated sensors towards H2O2 is conducted. Amperometric sensing response of PB screen printed sensor to H2O2 has limit of detection (LOD) of 0.5 μM with sensitivity of 63.690 mAcm-2/mM. Sensing response is found to be linear for the range, 1 to 4500 μM. While the CoPC screen printed sensor has LOD 0.05 μM with sensitivity of 56.66 mA cm-2/mM to H2O2. The response is linear for the range, 0.1 to 7500 μM. Glucose oxidase is immobilized on the working electrodes by cross-linking method using Glutaraldehyde and Nafion. Electrochemical sensing responses of the fabricated sensors for glucose are studied. PB mediated glucose sensor exhibits a sensitivity of 5.60 mA cm-2/mM with LOD of 7 μM. The response is observed to be linear for the range, 10 to1000 μM with linearity co-efficient of 0.9990. Sensitivity and LOD of CoPC mediated glucose sensor are found to be 5.224 mA cm-2/mM and 70 μM respectively. The amperometeric response is linear for the range, 100 to 1500 μM with linearity co-efficient of 0.9973. Inference studies on the fabricated glucose sensors are conducted with species like uric acid and ascorbic acid. PB mediated sensors showed a completely interference-free behavior, while CoPC mediated sensors are influenced by uric acid and ascorbic acid due to higher operating voltage. The sensing response of PB mediated glucose sensors is also studied in diluted human serum samples and the results are compared with values obtained by standard spectrometric method. The correlation co-efficient is found to be 0.935 and hence the sensor has potential application in clinical diagnostics.

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(Invited) Ionic Fluids Containing Both Strongly and Weakly Interacting Ions of the Same Charge Have Unique Ionic and Thus Chemical Environments As a Function of Ion Concentration
Authors: Rogers Robin Don , Wang Hui 
Published: February 2020

Liquid multi-ion systems or Double Salt Ionic Liquids (DSILs; salts composed of more than two types of ions, liquid at low temperature (below 100 °C),[1]) made by combining two or more salts can exhibit charge ordering and interactions not found in the parent salts, leading to new sets of properties. This effect is investigated here by examining liquid systems made by mixing two miscible ionic liquids comprised of a single cation, 1-ethyl-3-methylimidazolium ([C2mim]+), and two anions with very different properties, acetate ([OAc]-) and bis(trifluoromethylsulfonyl)imide ([NTf2]-), namely [C2mim][OAc]x[NTf2](1-x), and made by dissolving a crystalline salt, ammonium acetate ([NH4][OAc]), in the ionic liquid [C2mim][OAc] in their miscible range, namely [NH4]x[C2mim](1-x)[OAc] (0 ≤ x ≤ 0.58). Through NMR and FT-IR spectroscopic analysis, we have shown that the electrostatic interactions present are quite different from those in the parent salts. We attribute this to the unique charge ordering arising from the ability of [OAc]- to form complexes with [C2mim]+ ions by drawing [C2mim]+ ions away from the less basic [NTf2]- ions or the ability of [NH4]+ cation to form complexes with [OAc]- ions by “stealing” [OAc]- from the less acidic [C2mim]+ ions. Solubility studies with various kinds of organic solutes (e.g., EtOAc, H2O, chloroform, benzene, tetrahydrofuran) and active pharmaceutical ingredients (ibuprofen and diphenhydramine) indicate that the solubilities of these solutes in the DSILs show dramatic, non-linear trends as a function of ion concentration, demonstrating that solubility of selected solutes can be finely tuned via changes in the ionic compositions. These kinds of DSILs provide potential solvent systems with unique and tunable properties to be used in the electrochemical and separation fields.

References

[1]. G. Chatel, J. F. B. Pereira, V. Debbeti, H. Wang and R. D. Rogers, Green Chem., 16, 2051 (2014).
(Invited) Ionic Liquids in Gas Sensors: Recent Progress and Future Prospects
Authors: Carter Michael T , Stetter Joseph R , Findlay Melvin W , Patel Vinay 
Published: February 2020

Since the initial report of Hurley and Weir in 1951 [1] room temperature ionic liquids (RTILs) have been researched extensively for over five decades, starting with the binary eutectic mixtures based on haloaluminates [2,3] and proceeding through a wide array of single component salts containing many different organic cations and organic or inorganic anions [4-6]. The driving force behind research into these media was not only the sheer novelty of them as opposed to molecular liquids, but also the promise of new properties and capabilities, for example, in enabling improved separations, more efficient chemical syntheses and higher performance sensors and analytical methods. These possibilities are all the more interesting because the single component salts are typically air and moisture stable and therefore much easier to work with under practical conditions than the reactive haloaluminates, which need to be kept under dry, inert atmosphere.
Our particular interest as a commercial gas sensor developer and manufacturer is whether and how RTILs could be leveraged to improve amperometric gas sensor performance, most importantly in ways that add value to the sensor product from the customer’s point of view. We are using a new, next generation amperometric gas sensing technology for a variety of toxic gases and gases of environmental interest including CO, H2S, NO2, SO2, O3, NH3 and others. This approach adapts the conventional ideas of amperometric gas sensing into a printed package that is very small and ultralow power for modern applications (Figure 1). Can RTILs be used effectively as electrolytes in amperometric gas sensors? How do RTILs compare to conventional aqueous acid electrolytes? Can RTILs impart new capabilities and performance improvements (sensitivity, response time, stability, operational life, tolerance of extreme environmental conditions) to amperometric sensors? How does one go about selecting the right RTIL from the vast array of possibilities? What are the materials compatibility issues? What about cost?
This presentation will address these issues from the perspective of several programs on gas sensor development for toxic and environmental gases at KWJ Engineering.
References
[1] F. H. Hurley and T. P. Weir, J. Electrochem. Soc., 98, 203 (1951).
[2] H. L. Chum, V. R. Koch, L. L. Miller and R. A. Osteryoung, J. Am. Chem. Soc., 97, 3264 (1975).
[3] J. S Wilkes, J. A. Levisky, R. A. Wilson and C. L. Hussey, Inorg. Chem., 21, 1263 (1982).
[4] J. S. Wilkes and M. J. Zaworotko, Chem. Commun., 965 (1992).
[5] J. G. Huddleston, A. E. Visser, W. M. Reichert, H. D. Willauer, G. A Broker and R. D. Rogers, Green Chemistry, 3, 256 (2001).
[6] P. Wasserscheid and T. Welton (Eds.), “Ionic Liquids in Synthesis,” Wiley-VCH, Weinheim (2003).
Figure 1. Printed amperometric gas sensor (15 x 15 x 1 mm).

Figure 1
Transparent Nanowire Electrodes As a Tool for Electrochemical Detection
Authors: Lefèvre Florent , Poorahong Sujittra , Perron Marie-Claude , Juneau Philippe , Izquierdo Ricardo 
Published: February 2020

The development of new nanomaterial like carbon nanotubes, graphene and nanowires brings new possibilities to existing technologies. With the emergence of transparent electrode based on these materials, we could imagine new type of sensors, which combines transparency and flexibility. Silver nanowire transparent electrodes are currently transforming this industry. Touch screen sensors, OLED and solar panel can now be fabricated on flexible plastic sheets with low cost printing techniques. In the same way, this new type of electrode could bring electrochemical sensor toward new transparent and flexible sensing application for life science.
In our study, we fabricate and characterize transparent electrode based in metal nanowires for electrochemical detection. By changing the length, diameter and amount of deposited nanowires, we can vary their transparency (up to 90% transparent), sheet resistance (up to 0.1 ohm/square) and effective surface area. Compared to conventional evaporated plain electrodes, printed nanowire electrodes can achieve more than 80% transparency (in visible range) with the same electrochemical effective surface area. Using these electrodes, we can fabricate new sensors with high transparency (> 90%), flexibility and high sensitivity to oxygen and hydrogen peroxide. The detection of these two components is predominant in healthcare and environmental monitoring.
The combination of those properties could allow us to use this type of sensors as opto-electrochemical sensors for monitoring living cells and also for glucose detection on humans. Transparent nanowire electrodes can also be a real alternative to existing indium tin oxide (ITO) transparent electrodes for other applications.
Figure 1.Pictures of electrochemical sensors based on metal nanowires on PET transparent substrate. WE and REF electrodes are made from metal nanowire have 80% transparency, CE electrode are made from gold.
Figure 2. SEM image of silver nanowire electrode and the size distribution of nanowires.
Figure 3. Voltammetry response of the nanowire based electrochemical sensor to hydrogen peroxide in phosphate buffer (pH=7)
Figure 4. Dose-response curve to hydrogen peroxide using the nanowire-based sensor in phosphate buffer (pH=7)

Figure 1