jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Agnieszka Gola | Andrea Bernardi | Gianfranco Pasut | Witold Musiał
Source: Polymers (article, 2021-03-24)
Field: Materials Science — Polymers and Plastics

The Influence of Initiator Concentration on Selected Properties of Thermosensitive Poly(Acrylamide-co-2-Acrylamido-2-Methyl-1-Propanesulfonic Acid) Microparticles Thermosensitive polymers PS1-PS5 were synthesized via the surfactant free precipitation polymerization (SFPP) using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA), and potassium persulfate (KPS) at 70 °C in aqueous environment. The effect of KPS concentrations on particle size and lower critical temperature solution (LCST) was examined by dynamic light scattering (DLS). The conductivity in the course of the synthesis and during cooling were investigated. The structural studies were performed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), H nuclear magnetic resonance (<sup>1</sup>H NMR), thermogravimetric analysis (TGA/DTA) and powder X-ray diffraction (PXRD). ATR-FTIR, <sup>1</sup>H NMR and PXRD data confirmed the polymeric nature of the material. TGA/DTA curves demonstrated thermal stability up to approx. 160 °C. The effect of temperature on the hydrodynamic diameter (HD) and zeta potential (ZP) were evaluated by dynamic light scattering (DLS) and electrophoretic mobility (EM) in 18-45 °C range. The LCST values were between 30 and 34 °C. HD and polydispersity index (PDI) of aqueous dispersions of the synthesized polymers PS1-PS5 at 18 °C were found to be 226 ± 35 nm (PDI = 0.42 ± 0.04), 299 ± 145 nm (PDI = 0.49 ± 0.29), 389 ± 39 nm (PDI = 0.28 ± 0.07), 584 ± 75 nm (PDI = 0.44 ± 0.06), and 271 ± 50.00 nm (PDI = 0.26 ± 0.14), respectively. At 18 °C the ZPs of synthesized polymers suspensions were -13.14 ± 2.85 mV, -19.52 ± 2.86 mV, -7.73 ± 2.76 mV, -7.99 ± 1.70 mV, and -9.05 ± 2.60 mV for PS1-PS5, respectively. We found that the initiator concentration influences the physicochemical properties of products including the size of polymeric particles and the LCST. Dynamic light scattering ; Dispersity ; Thermogravimetric analysis ; Lower critical solution temperature ; Potassium persulfate ; Materials science ; Aqueous solution ; Fourier transform infrared spectroscopy ; Polymer chemistry ; Polymerization ; Zeta potential ; Polymer ; Thermal stability ; Attenuated total reflection ; Nuclear chemistry ; Analytical Chemistry (journal) ; Chemistry ; Chemical engineering ; Copolymer ; Physical chemistry ; Organic chemistry ; Nanotechnology ; Nanoparticle Conducting polymers and applications ; Hydrogels: synthesis, properties, applications ; Advanced Polymer Synthesis and Characterization
Authors: Celia Llamazares | Natalia Sanz del Olmo | Juán Soliveri | F. Javier de la Mata | José Luis Copa-Patiño | Sandra García‐Gallego
Source: Antibiotics (article, 2021-05-17)
Field: Chemistry — Organic Chemistry

Insight on the Structure-to-Activity of Carbosilane Metallodendrimers in the Fight against Staphylococcus aureus Biofilms Biofilm formation is a critical health concern, involved in most human bacterial infections. Combatting this mechanism, which increases resistance to traditional antibiotics and host immune defences, requires novel therapeutic approaches. The remarkable biocide activity and the monodispersity of carbosilane metallodendrimers make them excellent platforms to evaluate the impact of different structural parameters on the biological activity. In this work, we explore the influence of iminopyridine ring substituents on the antibacterial activity against planktonic and biofilm <i>Staphylococcus aureus</i>. New families of first-generation Ru(II) and Cu(II) metallodendrimers were synthesised and analysed, in comparison to the non-substituted counterparts. The results showed that the presence of methyl or methoxy groups in <i>meta</i> position to the imine bond decreased the overall positive charge on the metal ion and, subsequently, the activity against planktonic bacteria. However, it seemed a relevant parameter to consider for the prevention of biofilm formation, if they contribute to increasing the overall lipophilicity. An optimum balance of the charge and lipophilicity of the metallodrug, accomplished through structural design, will provide effective biocide agents against bacteria biofilms. Staphylococcus aureus ; Biofilm ; Microbiology ; Chemistry ; Biology ; Bacteria ; Paleontology Antimicrobial agents and applications ; Organoboron and organosilicon chemistry ; Bacterial biofilms and quorum sensing
Authors: Yitao Liao | Tao Liu | Xiaohui Du | Xionghou Gao
Source: Frontiers in Chemistry (article, 2021-03-08)
Field: Materials Science — Materials Chemistry

Distribution of Iron on FCC Catalyst and Its Effect on Catalyst Performance The effects of different iron contamination content on the formation of iron nodules and the performance of FCC catalysts have been studied by cyclic deactivation treatment using iron naphthenate. The catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, and SEM. The catalysts' performance was evaluated by the Advanced Cracking Evaluation device. It has been found that there will be obvious nodulation on the catalyst when the iron concentration exceeds 7,400 μg/g. With the iron deposition from 53 μg/g to 11,690 μg/g, the crystal structure of zeolite will not be destroyed by iron. The surface area and pore volume of the catalyst decreased significantly; the surface area decreased from 125.3 m<sup>2</sup>/g to 91.0 m<sup>2</sup>/g, and the pore volume decreased from 0.21 cm<sup>3</sup>/g to 0.16 cm<sup>3</sup>/g. The studies also showed that the increase of iron deposition will lead to the decrease of catalytic reaction efficiency. With the iron deposition from 53 μg/g to 11,690 μg/g, the conversion decreased by 4.83%. Under the same 78 wt.% conversion, bottoms yield and coke yield increased by 2.15% and 1.31%, while gasoline yield and LCO yield decreased by 2.59% and 2.16%, respectively. The real state of the industrial iron contaminated equilibrium catalyst can be mimicked by using the cyclic deactivation method. Catalysis ; Yield (engineering) ; Coke ; Deposition (geology) ; Fluid catalytic cracking ; Adsorption ; Desorption ; Chemistry ; Zeolite ; Volume (thermodynamics) ; Chemical engineering ; Materials science ; Inorganic chemistry ; Nuclear chemistry ; Metallurgy ; Organic chemistry Catalytic Processes in Materials Science ; Catalysts for Methane Reforming ; Catalysis and Hydrodesulfurization Studies
Authors: Jeyaraj Belinda Asha | Murugan Karthik | Palaniswamy Suresh
Source: Materials Advances (article, 2021-01-01)
Field: Chemistry — Spectroscopy

Graphene oxide-derived carbonaceous sensor: turn-off fluorescence sensor for nanomolar detection of ruthenium ions in aqueous medium A novel covalently modified graphene oxide has been synthesised and demonstrated as a carbonaceous chemosensor for the selective detection of Ru(<sc>iii</sc>) in complete water medium. Graphene ; Ruthenium ; Oxide ; Fluorescence ; Covalent bond ; Aqueous solution ; Ion ; Aqueous medium ; Chemistry ; Ruthenium oxide ; Photochemistry ; Selectivity ; Inorganic chemistry ; Materials science ; Nanotechnology ; Catalysis ; Organic chemistry Molecular Sensors and Ion Detection ; Advanced biosensing and bioanalysis techniques ; Electrochemical sensors and biosensors
Authors: Yong Ren | Lei Zhou | Xin Li
Source: Frontiers in Chemistry (article, 2021-12-24)
Field: Materials Science — Materials Chemistry

Red-Shift (2-Hydroxyphenyl)-Benzothiazole Emission by Mimicking the Excited-State Intramolecular Proton Transfer Effect Novel strategies to optimize the photophysical properties of organic fluorophores are of great significance to the design of imaging probes to interrogate biology. While the 2-(2-hydroxyphenyl)-benzothiazole (HBT) fluorophore has attracted considerable attention in the field of fluorescence imaging, its short emission in the blue region and low quantum yield restrict its wide application. Herein, by mimicking the excited-state intramolecular proton transfer (ESIPT) effect, we designed a series of 2-(2-hydroxyphenyl)-benzothiazole (HBT) derivatives by complexing the heteroatoms therein with a boron atom to enhance the chance of the tautomerized keto-like resonance form. This strategy significantly red-shifted the emission wavelengths of HBT, greatly enhanced its quantum yields, and caused little effect on molecular size. Typically, compounds <b>12B</b> and <b>13B</b> were observed to emit in the near-infrared region, making them among the smallest organic structures with emission above 650 nm. Benzothiazole ; Intramolecular force ; Photochemistry ; Heteroatom ; Quantum yield ; Fluorophore ; Excited state ; Fluorescence ; Chemistry ; Solvatochromism ; Photoluminescence ; Materials science ; Molecule ; Optoelectronics ; Atomic physics ; Stereochemistry ; Organic chemistry ; Optics Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research ; Photochemistry and Electron Transfer Studies
Authors: Sebastian B. Beil | Max von Delius
Source: Organic Materials (article, 2021-04-01)
Field: Chemistry — Organic Chemistry

Supramolecular Approaches for Taming the Chemo- and Regiochemistry of C60 Addition Reactions The chemo- and regioselective functionalization of fullerenes is a long-standing problem of organic synthesis. Over the past five years, this fundamental challenge has gained technological relevance, because studies on single bis-adduct isomers in new-generation solar cells have demonstrated that the widespread use of isomer mixtures leads to suboptimal power conversion efficiencies. Herein, we review recent work on supramolecular approaches for achieving chemo- and regioselective syntheses of multiply functionalized derivatives of C60. Regioselectivity ; Supramolecular chemistry ; Fullerene ; Adduct ; Surface modification ; Combinatorial chemistry ; Chemistry ; Nanotechnology ; Organic chemistry ; Materials science ; Molecule ; Catalysis Fullerene Chemistry and Applications ; Organic Electronics and Photovoltaics ; Boron and Carbon Nanomaterials Research
Authors: Zhen Xu | Duane Hean | Clàudia Climent | David Casanova | Michael O. Wolf
Source: Materials Advances (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Switching between TADF and RTP: anion-regulated photoluminescence in organic salts and co-crystals Anions in organic salts are used to tune photoluminescence properties, especially TADF and RTP. Bromide facilitates RISC and give short delayed lifetimes while tetrafluoroborate leads to RTP with afterglow. Photoluminescence ; Ion ; Materials science ; Photochemistry ; Chemistry ; Optoelectronics ; Organic chemistry Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection ; Organic Light-Emitting Diodes Research
Authors: Khizar Mushtaq | Pui May Chou | Chin Wei Lai
Source: MATEC Web of Conferences (article, 2021-01-01)
Field: Materials Science — Polymers and Plastics

Review on the Synthesis Methods of Nano-Tungsten Oxide Dihydrate Colloid Tungsten being a transition element, forms oxide compounds of various oxidation states that enables it to form nanocolloids of tungsten oxide dihydrate. Multiple methods have been used in recent years to synthesize nano tungsten oxide dihydrate, including sol-gel synthesis, electrochemical deposition, hydrothermal synthesis and anodization. However, a universally accepted synthesis method for this material is not offered. The most appropriate method and its corresponding processing parameters for the synthesis of nano tungsten oxide dihydrate colloids were presented in the present study. The objective of the present study was to investigate the effect of processing parameters, i.e. applied voltage, temperature and anodizing duration on the particle size of nanocolloids. It is found that anodization is the easiest, efficient, and cost-effective method to synthesize the colloidal solution of nano tungsten oxide dihydrate. Conducting the synthesis at room temperature at a voltage of 50 V for 60 minutes yields the product with particle size of 40 – 60 nm, which can be used in wide array of applications. This paper also highlights the research gaps for future work and gives recommendations to extend this study particularly for the industrial application of tungsten oxide. Anodizing ; Tungsten ; Materials science ; Oxide ; Tungsten oxide ; Nano- ; Particle size ; Colloid ; Chemical engineering ; Nanotechnology ; Nanoparticle ; Inorganic chemistry ; Metallurgy ; Chemistry ; Composite material Transition Metal Oxide Nanomaterials ; Catalysis and Oxidation Reactions ; Gas Sensing Nanomaterials and Sensors
Authors: Artemis Tsagdi | Ioannis Drossos | D. Georgiou | Stylianos Exarhopoulos | Georgios Karasiotas | Joannis K. Kallitsis | Eleni P. Kalogianni
Source: Polymers (article, 2021-01-18)
Field: Materials Science — Polymers and Plastics

Injection Molded PP Foams Using Food Ingredients for Food Packaging Applications A new approach to the creation of polypropylene (PP) based foaming materials was developed using food grade foaming agents that were coated on the PP pellets. More specifically, sodium bicarbonate and organic acids were used to coat PP pellets using either polyethyleneoxide (PEO) or lipid esters as coating stabilizers. In order to overcome the problem of the thermal decomposition of sodium bicarbonate at temperatures lower than the PP melting temperature, which makes the direct foaming during melt mixing impossible, the proposed methodology was proved quite efficient. Thus, new PP masterbatches were prepared, where the foaming agents were incorporated as coating at PP pellets at contents up to 10%, and initially used in Lab scale injection machines in order to find the best combination of materials that resulted in the production of foamed articles. Subsequently selected material combinations were tested in an industrial scale injection molding machine, where an optimization of the injection parameters was attempted. The outcome of this was the production of PP articles with significantly increased void fraction, up to 14%, decreased thermal conductivity, up to 20%, and various pore sizes as was observed via microscopic examination using SEM and CLSM. Materials science ; Sodium bicarbonate ; Polypropylene ; Pellets ; Blowing agent ; Molding (decorative) ; Composite material ; Coating ; Chemical engineering ; Foaming agent ; Food packaging ; Compatibility (geochemistry) ; Thermal stability ; Thermal decomposition ; Porosity ; Chemistry ; Polyurethane ; Organic chemistry ; Food science Polymer Foaming and Composites ; biodegradable polymer synthesis and properties ; Carbon dioxide utilization in catalysis
Authors: Merian Crumbach | Jonas Bachmann | Lars Fritze | Andreas Helbig | Ivo Krummenacher | Holger Braunschweig | Holger Helten
Source: Angewandte Chemie (article, 2021-02-01)
Field: Chemistry — Organic Chemistry

Dithiophene‐Fused Oxadiborepins and Azadiborepins: A New Class of Highly Fluorescent Heteroaromatics Abstract Access to dithiophene‐fused oxadiborepins and the first azadiborepins attained via a modular synthesis route are presented. The new compounds emit intense blue light, some of which demonstrate fluorescence quantum yields close to unity. Cyclic voltammetry (CV) revealed electrochemically reversible one‐electron reduction processes. The weak aromatic character of the novel 1,2,7‐azadiborepin ring is demonstrated with in‐depth theoretical investigations using nucleus‐independent chemical shift (NICS) scans and anisotropy of the induced current density (ACID) calculations. Fluorescence ; Cyclic voltammetry ; Ring (chemistry) ; Chemistry ; Photochemistry ; Density functional theory ; Anisotropy ; Character (mathematics) ; Materials science ; Computational chemistry ; Electrochemistry ; Physical chemistry ; Organic chemistry ; Electrode ; Physics ; Optics Organoboron and organosilicon chemistry ; Organic and Molecular Conductors Research ; Organic Light-Emitting Diodes Research
Authors: Rouven F. Pfleger | Sören Schlittenhardt | Marcel P. Merkel | Mario Ruben | Karin Fink | C. Anson | Jesper Bendix | Annie K. Powell
Source: Chemistry - A European Journal (article, 2021-10-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Terminal Ligand and Packing Effects on Slow Relaxation in an Isostructural Set of [Dy(H<sub>2</sub>dapp)X<sub>2</sub>]<sup>+</sup> Single Molecule Magnets** We report three structurally related single ion Dy compounds using the pentadentate ligand 2,6-bis((E)-1-(2-(pyridin-2-yl)-hydrazineylidene)ethyl)pyridine (H<sub>2</sub> dapp) [Dy(H<sub>2</sub> dapp)(NO<sub>3</sub> )<sub>2</sub> ]NO<sub>3</sub> (1), [Dy(H<sub>2</sub> dapp)(OAc)<sub>2</sub> ]Cl (2) and [Dy(H<sub>2</sub> dapp)(NO<sub>3</sub> )<sub>2</sub> ]Cl<sub>0.92</sub> (NO<sub>3</sub> )<sub>0.08</sub> (3). The (H<sub>2</sub> dapp) occupies a helical twisted pentagonal equatorial arrangement with two anionic ligands in the axial positions. Further influence on the electronic and magnetic structure is provided by a closely associated counterion interacting with the central N-H group of the (H<sub>2</sub> dapp). The slow relaxation of the magnetisation shows that the anionic acetates give the greatest slowing down of the magnetisation reversal. Further influence on the relaxation properties of compounds1 and 2 is the presence of short nitrate-nitrate intermolecular ligand contact opening further lattice relaxation pathways. Isostructural ; Ligand (biochemistry) ; Crystallography ; Molecule ; Terminal (telecommunication) ; Relaxation (psychology) ; Materials science ; Magnet ; Single-molecule magnet ; Chemistry ; Physics ; Magnetization ; Crystal structure ; Magnetic field ; Computer science ; Receptor Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Organic and Molecular Conductors Research
Authors: Yi-Fang Chen | Jia-Wen Hong | Jung-Hong Chang | Belda Amelia Junisu | Ya‐Sen Sun
Source: Polymers (article, 2021-07-28)
Field: Materials Science — Materials Chemistry

Influence of Osmotic Pressure on Nanostructures in Thin Films of a Weakly-Segregated Block Copolymer and Its Blends with a Homopolymer We studied the influence of osmotic pressure on nanostructures in thin films of a symmetric weakly-segregated polystyrene-block-poly (methyl methacrylate), P(S-b-MMA), block copolymer and its mixtures with a polystyrene (PS) homopolymer of various compositions. Thin films were deposited on substrates through surface neutralization. The surface neutralization results from the PS mats, which were oxidized and cross-linked by UV-light exposure. Thus, thermal annealing produced perpendicularly oriented lamellae and perforated layers, depending on the content of added PS chains. Nevertheless, a mixed orientation was obtained from cylinders in thin films, where a high content of PS was blended with the P(S-b-MMA). A combination of UV-light exposure and acetic acid rinsing was used to remove the PMMA block. Interestingly, the treatment of PMMA removal inevitably produced osmotic pressure and consequently resulted in surface wrinkling of perpendicular lamellae. As a result, a hierarchical structure with two periodicities was obtained for wrinkled films with perpendicular lamellae. The formation of surface wrinkling is due to the interplay between UV-light exposure and acetic acid rinsing. UV-light exposure resulted in different mechanical properties between the skin and the inner region of a film. Acetic acid rinsing produced osmotic pressure. It was found that surface wrinkling could be suppressed by reducing film thickness, increasing PS content and using high-molecular-weight P(S-b-MMA) BCPs. Copolymer ; Materials science ; Polystyrene ; Thin film ; Methyl methacrylate ; Polymer chemistry ; Chemical engineering ; Annealing (glass) ; Surface modification ; Composite material ; Acetic acid ; Perpendicular ; Polymer ; Nanotechnology ; Chemistry ; Organic chemistry Block Copolymer Self-Assembly ; Advanced Polymer Synthesis and Characterization ; Advanced Materials and Mechanics
Authors: Jie Gao | Yutaka Okazaki | Émilie Pouget | Sylvain Nlate | Brice Kauffmann | Franck Artzner | Thierry Buffeteau | Reïko Oda
Source: Materials Chemistry Frontiers (article, 2021-01-01)
Field: Materials Science — Biomaterials

Slow kinetic evolution of nanohelices based on gemini surfactant self-assemblies with various enantiomeric excess; chiral segregation towards a racemic mixture Very slow kinetic evolution (days) of chiral nanoribbons based on amphiphilic molecular assemblies is investigated for various enantiomeric excess. Enantiomer ; Pulmonary surfactant ; Amphiphile ; Materials science ; Kinetic energy ; Enantiomeric excess ; Chirality (physics) ; Kinetic resolution ; Chemical engineering ; Chemistry ; Organic chemistry ; Enantioselective synthesis ; Copolymer ; Catalysis ; Chiral symmetry ; Physics ; Composite material Supramolecular Self-Assembly in Materials ; Surface Chemistry and Catalysis ; Synthesis and Properties of Aromatic Compounds
Authors: Pedro B. Groszewicz
Source: Open Ceramics (article, 2021-03-01)
Field: Materials Science — Materials Chemistry

NMR spectroscopy of electroceramics – Applications to lead-free perovskite oxides Understanding about the local structure plays an increasing role for the discovery of structure-property relations in electroceramics. Despite that, characterization techniques dedicated to the local structure are still not widespread in the electroceramics community. Nuclear magnetic resonance spectroscopy (NMR) has the potential to close this gap, as particularly sensitive to minute distortions and well-suited for the structural analysis of partially disordered materials, such as solid-solutions. This review aims at an introduction of this technique tailored to the materials scientist. Following a brief description of the base concepts, its capabilities are demonstrated by a series of tangible examples from local structural questions pertinent to materials based on three classes of lead-free perovskites, namely BaTiO3, NaNbO3 and Na1/2Bi1/2TiO3. Beyond its application to lead-free perovskite oxides, the concepts illustrated here are of broad interest for further oxides and materials in general. Electroceramics ; Characterization (materials science) ; Perovskite (structure) ; Spectroscopy ; Materials science ; Nanotechnology ; Lead (geology) ; Nuclear magnetic resonance spectroscopy ; Engineering physics ; Chemistry ; Physics ; Nuclear magnetic resonance ; Crystallography Ferroelectric and Piezoelectric Materials ; Multiferroics and related materials ; Solid-state spectroscopy and crystallography