jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Dandan Gao | Ivan Trentin | Ludwig Schwiedrzik | Leticia González | Carsten Streb
Source: Preprints.org (preprint, 2019-12-22)
Field: Materials Science — Materials Chemistry

Reactivity and Stability of Polyoxometalate Water Oxidation Electrocatalysts This review describes major advances in the use of functionalized molecular metal oxides (polyoxometalates, POMs) as water oxidation catalysts under electrochemical conditions. The fundamentals of POM-based water oxidation are described together with a brief overview of general approaches to designing POM water oxidation catalysts. Next, the use of POMs for homogeneous, solution-phase water oxidation is described together with a summary of theoretical studies shedding light on the POM-WOC mechanism. This is followed by a discussion of heterogenization of POMs on electrically conductive substrates for technologically more relevant application studies. Stability of POM water oxidation catalysts are discussed on selected examples where detailed data is already available. The review finishes with an outlook on future perspective and emerging themes in electrocatalytic polyoxometalate-based water oxidation research. Polyoxometalate ; Homogeneous ; Catalysis ; Electrochemistry ; Catalytic oxidation ; Chemistry ; Reactivity (psychology) ; Chemical engineering ; Materials science ; Inorganic chemistry ; Organic chemistry ; Physical chemistry ; Electrode ; Engineering Polyoxometalates: Synthesis and Applications ; Advanced oxidation water treatment ; Electrocatalysts for Energy Conversion
Authors: Evgeniia A. Stepanidenko | Yulia Gromova | Tatiana Kormilina | Sergei A. Cherevkov | D. A. Kurshanov | Aliaksei Dubavik | М. А. Баранов | Oleg Medvedev | A. V. Fëdorov | Yurii K. Gun’ko | Elena V. Ushakova | А. В. Баранов
Source: Scientific Reports (article, 2019-01-24)
Field: Materials Science — Materials Chemistry

Porous flower-like superstructures based on self-assembled colloidal quantum dots for sensing Quantum dots (QDs) have been envisaged as very promising materials for the development of advanced optical sensors. Here we report a new highly porous luminescent material based on colloidal QDs for potential applications in optical sensing devices. Bulk flower-like porous structures with sizes of hundreds of microns have been produced by slow destabilization of QD solution in the presence of a non-solvent vapor. The porous highly luminescent material was formed from CdSe QDs using the approach of non-solvent destabilization. This material demonstrated a 4-fold decrease in PL signal in the presence of the ammonia vapor. The relationship between the destabilization rate of QDs in solution and the resulting morphology of structural elements has been established. The proposed model of bulk porous flower-like nanostructured material fabrication can be applied to nanoparticles of different nature combining their unique properties. This research opens up a new approach to design novel multi-component composite materials enabling potential performance improvements of various photonic devices. Quantum dot ; Materials science ; Porosity ; Nanotechnology ; Fabrication ; Luminescence ; Colloid ; Self-assembly ; Photonics ; Nanoparticle ; Composite number ; Nanocrystal ; Porous medium ; Optoelectronics ; Chemical engineering ; Composite material Quantum Dots Synthesis And Properties ; Gold and Silver Nanoparticles Synthesis and Applications ; Photonic Crystals and Applications
Authors: Samah Yousef | Nevin Ibrahim | Souzy S. Farag | Adel A. El-Mehalawy | Ahmed A. Ismaiel | Ashraf S. Ahmed
Source: Egyptian Journal of Microbiology (article, 2019-09-10)
Field: Materials Science — Materials Chemistry

Mycosynthesis of Silver Nanoparticles by an Endophytic Fungus Alternaria tenuissima and Evaluation of Their Antimicrobial and Antioxidant Effect GREEN synthetic strategies have been receiving a great interest for metal nanoparticles synthesis. In the current study, extracellular synthesis of silver nanoparticles (AgNPs) using the cell filtrate of the endophytic fungus, Alternaria tenuissima AUMC 13621 isolated from healthy leaves of Ruta graveolens plant, was achieved. The biosynthesized AgNPs were characterized by UV–visible spectroscopy, transmission electron microscopy (TEM), dynamic light scattering analysis (DLS), and fourier transform infra-red (FT-IR), The UV–visible spectrum shows a maximum absorption peak at 416nm. TEM photography showed the spherical shape of AgNPs with an average size 9.8nm. FT-IR indicates bounding of silver nanoparticles with the supernatant molecules of A. tenuissima and provides evidence for the presence of proteins and biomolecules responsible for reduction of Ag+ to Ag0, capping and stabilizing the synthesized AgNPs. Parametric optimization for the biosynthesis process showed maximum absorbance of 400–408nm at pH-12, 70oC using 1mM AgNO3 concentration. By studying the effect of gamma irradiation on AgNPs biosynthesis, the results showed that, the obtained peak became more sharper and narrower moreover, the absorbance intensity increased by increasing irradiation dose from 0.5 to 3.0kGy. The synthesized Ag NPs have a potent antimicrobial activity to some tested pathogenic bacterial strains and Candida albicans ATCC1023. Additionally, they had excellent free radical scavenging activity. The AgNPs antioxidant activity at 100μg/ml was of 65.99% inhibition that was close to the result obtained for ascorbic acid (67.39%). Silver nanoparticle ; Absorbance ; Chemistry ; Ascorbic acid ; Nuclear chemistry ; Antioxidant ; Antimicrobial ; Dynamic light scattering ; Candida albicans ; Nanoparticle ; Food science ; Biochemistry ; Chromatography ; Botany ; Materials science ; Nanotechnology ; Organic chemistry ; Biology Nanoparticles: synthesis and applications ; Medicinal Plants and Neuroprotection
Authors: Christoph Göbel | Christian Hils | Markus Drechsler | Dirk Baabe | Andreas Greiner | Holger Schmalz | Birgit Weber
Source: Angewandte Chemie (article, 2019-12-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Confined Crystallization of Spin‐Crossover Nanoparticles in Block‐Copolymer Micelles Abstract Nanoparticles of the spin‐crossover coordination polymer [FeL(bipy)] n were synthesized by confined crystallization within the core of polystyrene‐ block ‐poly(4‐vinylpyridine) (PS‐ b ‐P4VP) diblock copolymer micelles. The 4VP units in the micellar core act as coordination sites for the Fe complex. In the bulk material, the spin‐crossover nanoparticles in the core are well isolated from each other allowing thermal treatment without disintegration of their structure. During annealing above the glass transition temperature of the PS block, the transition temperature is shifted gradually to higher temperatures from the as‐synthesized product ( T 1/2 ↓=163 K and T 1/2 ↑=170 K) to the annealed product ( T 1/2 ↓=203 K and T 1/2 ↑=217 K) along with an increase in hysteresis width from 6 K to 14 K. Thus, the spin‐crossover properties can be shifted towards the properties of the related bulk material. The stability of the nanocomposite allows further processing, such as electrospinning from solution. Copolymer ; Spin crossover ; Glass transition ; Micelle ; Crystallization ; Materials science ; Nanoparticle ; Polystyrene ; Annealing (glass) ; Polymer ; Chemical engineering ; Thermal stability ; Polymer chemistry ; Crystallography ; Nanotechnology ; Chemistry ; Physical chemistry ; Composite material Magnetism in coordination complexes ; Metal-Organic Frameworks: Synthesis and Applications ; Metal complexes synthesis and properties
Authors: Anna Palmé | Fredrik Aldaeus | Tomas Larsson | Merima Hasani | Hans Theliander | Harald Brelid
Source: BioResources (article, 2019-06-03)
Field: Materials Science — Biomaterials

Differences in swelling of chemical pulp fibers and cotton fibers – Effect of the supramolecular structure The swelling and dissolution of cellulose are key parameters in the production of regenerated cellulose fibers. Since cotton is almost pure cellulose, it has been proposed that the recycling of cotton textiles may be accomplished through incorporating the cotton textiles into the production of regenerated cellulosic fibers. In this study, the supramolecular structure before and after pretreatment was characterized using solid-state carbon-13 nuclear magnetic resonance (13C NMR), and the findings related to the swelling of dissolving pulp and cotton were quantified with a fiber analyzer. The cotton and dissolving pulp samples were subjected to three different pretreatments: mild acid hydrolysis, acid hydrolysis in ethanol, and a hydrothermal treatment. The results showed that cotton was harder to swell than the dissolving pulp. This indicated that either waste cotton requires another type of activating pretreatment than those included in this study or very good solvents if it is to be included in the production of regenerated fibers. Dissolving pulp ; Cellulose ; Swelling ; Pulp (tooth) ; Dissolution ; Materials science ; Acid hydrolysis ; Hydrolysis ; Cellulose fiber ; Pulp and paper industry ; Cellulosic ethanol ; Chemical engineering ; Fiber ; Composite material ; Nuclear chemistry ; Chemistry ; Organic chemistry Advanced Cellulose Research Studies
Authors: Timo Stein | Frank Hoffmann | Michael Fröba
Source: Dalton Transactions (article, 2019-01-01)
Field: Chemistry — Inorganic Chemistry

A new set of metal–organic frameworks synthesised from diisophthalate-based, 2′-phosphorus-substituted <i>m</i>-terphenyl linker molecules Four metal-organic frameworks employing the m-terphenyl diisophthalate linker molecule with 2' substitution by P(v)-based functional groups of the central aryl have been synthesised. The dense packing of POMe2/PSMe2 functional groups within UHM-60/UHM-61 (UHM: University of Hamburg Materials) with an underlying net of ucp topology was overcome by increasing the sterical demand of phosphorus substituents. Replacement of the PEMe2 (E = O, S) functional groups by POEt2 or POPh2 gave UHM-62 and UHM-63, respectively, where valid deconstructions of the underlying topology to types 3,3,4,4T199, tim, and tst were found. The potential influence of the now-accessible phosphoryl functional group towards CO2 and CH4 adsorption as well as the selectivity towards CO2/CH4 separation was studied. Based on a comprehensive survey of literature-known Cu(ii)-based MOFs with m-terphenyl-based linker molecules, we propose the deconstruction of inter-isophthalate plane angles to angular components of twist and fold allowing for the sophisticated classification of topologies that can be realised in Cu(ii)-based MOFs using the m-terphenyl tetracarboxylate linker molecule. Terphenyl ; Linker ; Molecule ; Metal-organic framework ; Phosphorus ; Metal ; Materials science ; Organic molecules ; Combinatorial chemistry ; Chemistry ; Nanotechnology ; Organic chemistry ; Computer science Metal-Organic Frameworks: Synthesis and Applications ; Metal complexes synthesis and properties ; Magnetism in coordination complexes
Authors: Graciela E. Negri | Eric G. Gharakhanian | Timothy J. Deming
Source: Macromolecular Bioscience (article, 2019-09-04)
Field: Materials Science — Biomaterials

Tunable, Functional Diblock Copolypeptide Hydrogels Based on Methionine Homologs The preparation of new diblock copolypeptide hydrogels derived from homologs of l-methionine, that is, l-homomethionine and l-6-(methylthio)-l-norleucine is described. Compared to l-methionine residues, use of l-methionine homologs allow improved copolymerization with l-leucine residues to give well-defined block copolypeptides. These copolypeptides are subsequently modified using robust thioether alkylation reactions employing a variety of functional epoxides, which yield samples capable of forming transparent, self-healing hydrogels in water. The facile variation of different functional epoxides for postpolymerization modification is found to allow predictable functionalization and tuning of hydrogel properties by the modification of simple precursors. Self-healing hydrogels ; Polymer chemistry ; Methionine ; Chemistry ; Biochemistry ; Amino acid Supramolecular Self-Assembly in Materials ; Chemical Synthesis and Analysis ; Click Chemistry and Applications
Authors: Ashutosh Mishra | Rakesh Kumar Trivedi
Source: RASAYAN Journal of Chemistry (article, 2019-01-01)
Field: Chemistry — Analytical Chemistry

SYNTHESIS AND CHARACTERIZATION OF BIOSURFACTANT USING WASTE FROM OIL PROCESSING INDUSTRY AS SUBSTRATE BY Pseudomonas aeruginosa (MTCC 424) The purpose of this study was to produce biosurfactant by the waste of vegetable oil (soya bean and rice bran) processing industries like spent bleaching earth which contains approximately 14 to 25% residual oil respectively. More oil % was found in the spent on rice bran so here the same was used. The spent bleaching earth is a type of waste solid substance which is generated as an ingredient of the cleansing and decolorization process in the edible oil industry. It is usually deposited in the landfills or waste dumps. Pseudomonas was selected for its nutritional and biochemical versatility as well as for the simplicity of the culture conditions. The process opted for the growth of bacteria was steam sterilization and dry heat sterilization followed by microbial culture in basal salt medium with residual oil. Further biosurfactant was screened by various examination methods such as surface tension measurement, emulsification assay E24, CTAB methylene blue assay, oil dislocation (displacement), drop collapse and effect of environmental factors on biosurfactant activity was studied. Rhamnolipid biosurfactant produced by Pseudomonasaeruginosa is determined by the formation of insoluble ion pairs with various cationic substances. Emulsification index (%) shows the positive result for drop collapse, oil displacement, and CTAB methylene blue assay. The NMR and FTIR analysis show that the concentration and purely screened Rhamnolipid product contained L-rhamnosyl-b-hydroxydecanoyl-b-hydroxydecanoate (RL1) and L-rhamnosyl L-rhamnosyl-bhydroxydecanoyl-bhydroxydecanoate (RL2). Effect of environmental factors like salt, temperature and pH on surface tension was studied to analyze the solubility of biosurfactant. The optimum pH was found 6.8 and the optimum concentration of rhamnolipids produced was 8.5 g/l. Pseudomonas aeruginosa ; Characterization (materials science) ; Substrate (aquarium) ; Waste management ; Pulp and paper industry ; Chemistry ; Microbiology ; Food science ; Business ; Materials science ; Bacteria ; Biology ; Engineering ; Nanotechnology ; Ecology Petroleum Processing and Analysis
Authors: Qiang Gao | Ingo Opahle | Oliver Gutfleisch | Hongbin Zhang
Source: arXiv (Cornell University) (preprint, 2019-09-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Designing rare-earth free permanent magnets in Heusler alloys via interstitial doping Based on high-throughput density functional theory calculations, we investigated the effects of light interstitial H, B, C, and N atoms on the magnetic properties of cubic Heusler alloys, with the aim to design new rare-earth free permanent magnets. It is observed that the interstitial atoms induce significant tetragonal distortions, leading to 32 candidates with large ($&gt;$ 0.4 MJ/m$^3$) uniaxial magneto-crystalline anisotropy energies (MAEs) and 10 cases with large in-plane MAEs. Detailed analysis following the the perturbation theory and chemical bonding reveals the strong MAE originates from the local crystalline distortions and thus the changes of the chemical bonding around the interstitials. This provides a valuable way to tailor the MAEs to obtain competitive permanent magnets, filling the gap between high performance Sm-Co/Nd-Fe-B and widely used ferrite/AlNiCo materials. Alnico ; Magnet ; Materials science ; Tetragonal crystal system ; Density functional theory ; Condensed matter physics ; Rare earth ; Alloy ; Doping ; Anisotropy ; Crystallography ; Crystal structure ; Metallurgy ; Computational chemistry ; Chemistry ; Optoelectronics ; Optics ; Physics Magnetic Properties of Alloys ; Heusler alloys: electronic and magnetic properties ; Magnetic properties of thin films
Authors: Johannes Staudt | Stephan Leyer | John K. Duchowski
Source: Coatings (article, 2019-03-28)
Field: Materials Science — Surfaces, Coatings and Films

Detailed Characterization of the Effect of Application of Commercially Available Surface Treatment Agents on Textile Wetting Behavior The change in the wetting behavior of a standard commercially available textile material in response to surface treatment has been thoroughly characterized with conventional laboratory measurement techniques. The characterization was carried out by taking a series of contact angle measurements that allowed for the determination of the corresponding shift in substrate surface energy as a result of the applied treatment. The collected surface energy values were expressed in terms of the spreading parameter S, which was used to describe phase behavior at the substrate/droplet interface. However, these results showed that the use of a coarse parameter S, or even the work of adhesion ( W a ) and the work of cohesion ( W c ) parameters alone did not adequately account for the observed wetting behavior. A proper description of droplet formation on substrate surface was provided only when the interfacial interaction was examined at a more detailed level by involving the individual dispersive ( σ l d , σ s d ) and polar ( σ l p , σ s p ) surface energy components of both the solid and the wetting liquid. The methodology for characterization of interactions between a textile substrate coated with various surface active agents and several functional fluids have been developed. Several practical examples of how this methodology can be applied to describe the substrate surface treatment and the resulting wetting behavior are described herein. Wetting ; Surface energy ; Contact angle ; Materials science ; Substrate (aquarium) ; Characterization (materials science) ; Wetting transition ; Adhesion ; Surface tension ; Textile ; Composite material ; Work (physics) ; Nanotechnology ; Thermodynamics ; Physics Surface Modification and Superhydrophobicity ; Nanomaterials and Printing Technologies ; Pickering emulsions and particle stabilization
Authors: Anete Joceline Benitez-Carreón | Jesús Guillermo Soriano‐Moro | Eduardo Vivaldo‐Lima | Ramiro Guerrero‐Santos | Alexander Penlidis
Source: Processes (article, 2019-11-10)
Field: Chemistry — Organic Chemistry

New Aspects on the Modeling of Dithiolactone-Mediated Radical Polymerization of Vinyl Monomers A kinetic model for the dithiolactone-mediated radical polymerization of vinyl monomers based on the persistent radical effect and reversible addition (negligible fragmentation) was used to calculate the polymerization rate and describe molar mass development in the polymerization of methyl methacrylate at 60 °C, using 2,2-azobisisobutyronitrile (AIBN) as an initiator, as well as dihydro-5-phenyl-2(3H)-thiophenethione (DTL1) and dihydro-2(3H)-thiophenethione (DTL2) as controllers. The model was implemented in the PREDICI commercial software. A good agreement between experimental data and model predictions was obtained. Azobisisobutyronitrile ; Polymerization ; Radical polymerization ; Reversible addition−fragmentation chain-transfer polymerization ; Chain transfer ; Polymer chemistry ; Monomer ; Living free-radical polymerization ; Methyl methacrylate ; Bulk polymerization ; Chemistry ; Kinetic chain length ; Organic chemistry ; Polymer Advanced Polymer Synthesis and Characterization ; Photopolymerization techniques and applications ; Antimicrobial agents and applications
Authors: Leevi Viitanen | Alisa Halonen | Eira Friström | Juha Koivisto | Marko Korhonen | Antti Puisto | Mikko J. Alava
Source: BioResources (article, 2019-06-03)
Field: Materials Science — Materials Chemistry

Constriction flow of cellulose laden air-aqueous foam Foams are encountered in everyday life across wide applications, e.g., in foods and cleaning products. They have also been widely used in different industries in processes such as flotation and oil recovery. The application of bio-based materials is a novel interest, and foam forming enables these materials to be used more flexibly. For efficient industrial usage, the flow of such materials must be well understood and characterized. This work measured the velocity field of nanocellulose laden foam in a two-dimensional Hele-Shaw cell with a constriction, using optical imaging and particle image velocimetry. The measurements showed that the addition of cellulose increased the effective viscosity of the liquid films. In a numerical simulation using the Giesekus polymer model, the experimental trend was reproduced through increasing the fluid’s viscosity. Adding highly viscoelastic nanofibrillated cellulose suspension to foam affected only the viscous component of the foam. The delayed elastic response did not change. Materials science ; Viscoelasticity ; Nanocellulose ; Viscosity ; Cellulose ; Composite material ; Rheology ; Particle image velocimetry ; Suspension (topology) ; Silicone oil ; Polymer ; Chemical engineering ; Mechanics Pickering emulsions and particle stabilization ; Polysaccharides Composition and Applications