jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Riccardo Chiarcos | Valentina Gianotti | Maurizio Cossi | Alberto Zoccante | Diego Antonioli | Katia Sparnacci | Michele Laus | Federica E. Caligiore | Michele Perego
Source: ACS Applied Electronic Materials (article, 2019-08-07)
Field: Materials Science — Surfaces, Coatings and Films

Thermal Degradation in Ultrathin Films Outperforms Dose Control of n-Type Polymeric Dopants for Silicon Polystyrene samples with different molar mass and narrow polydispersity index were prepared by nitroxide-mediated polymerization using N-tert-butyl-N-[1-diethylphosphono(2,2-dimethylpropyl)] nitroxide (SG1) as a radical controller and phosphorus containing moiety, and their doping performances were studied. In contrast to what is observed for conventional “grafting to” reactions, the thickness of the grafted layer is observed to rapidly increase with time, reaching a thickness plateau value that is significantly lower than 2 times the radius of gyration of the corresponding polymer chain. In addition, the plateau thickness initially increases as the molar mass of the grafting polymer increases and then reaches a somewhat limiting thickness. Interestingly, the phosphorus areal dose on the silicon surface is equal to the density of the grafted chains estimated from the thickness of the brush layer. The overall data indicate that during the high-temperature thermal treatment two parallel and competing reactions are operating, namely, the “grafting to” reaction and a degradation of the SG1 moiety that leads to fragments, as confirmed by direct exposure probe analysis. This combination results in a fine-tuning of the phosphorus dose at the substrate surface with a substantial outperforming of the dopant dose control, achieved by using conventional self-assembled monolayers. Molar mass ; Dopant ; Polymer ; Dispersity ; Polymer chemistry ; Silicon ; Polymerization ; Polystyrene ; Chemistry ; Analytical Chemistry (journal) ; Materials science ; Monolayer ; Chemical engineering ; Doping ; Nanotechnology ; Composite material ; Chromatography ; Organic chemistry ; Optoelectronics Polymer Surface Interaction Studies ; Molecular Junctions and Nanostructures ; Fuel Cells and Related Materials
Authors: N. S. Nesterov | Anton S. Shalygin | В. П. Пахарукова | Tatiana S. Glazneva | Oleg N. Martyanov
Source: The Journal of Supercritical Fluids (article, 2019-03-30)
Field: Materials Science — Materials Chemistry

Mesoporous aerogel-like Al-Si oxides obtained via supercritical antisolvent precipitation of alumina and silica sols Supercritical fluid ; Materials science ; Mesoporous material ; Aerogel ; Precipitation ; Chemical engineering ; Silicon ; Phase (matter) ; Supercritical drying ; Doping ; Mesoporous silica ; Nanotechnology ; Catalysis ; Metallurgy ; Organic chemistry ; Chemistry Catalytic Processes in Materials Science ; Mesoporous Materials and Catalysis ; Aerogels and thermal insulation
Authors: Kadir Mercan | E. Emsen | Ömer Cívalek
Source: Composite Structures (article, 2019-03-08)
Field: Materials Science — Materials Chemistry

Effect of silicon dioxide substrate on buckling behavior of Zinc Oxide nanotubes via size-dependent continuum theories Buckling ; Materials science ; Elasticity (physics) ; Zinc ; Substrate (aquarium) ; Composite material ; Silicon ; Nanowire ; Oxide ; Silicon dioxide ; Nanotechnology ; Metallurgy Nonlocal and gradient elasticity in micro/nano structures ; Composite Structure Analysis and Optimization ; Thermoelastic and Magnetoelastic Phenomena
Authors: Sait Elmas | Thomas J. Macdonald | William Skinner | Mats R. Andersson | Thomas Nann
Source: Polymers (article, 2019-01-10)
Field: Materials Science — Polymers and Plastics

Copper Metallopolymer Catalyst for the Electrocatalytic Hydrogen Evolution Reaction (HER) Conjugated polymers with stabilizing coordination units for single-site catalytic centers are excellent candidates to minimize the use of expensive noble metal electrode materials. In this study, conjugated metallopolymer, P<sub>OS</sub>[Cu], was synthesized and fully characterized by means of spectroscopical, electrochemical, and photophysical methods. The copper metallopolymer was found to be highly active for the electrocatalytic hydrogen generation (HER) in an aqueous solution at pH 7.4 and overpotentials at 300 mV vs. reversible hydrogen electrode (RHE). Compared to the platinum electrode, the obtained overpotential is only 100 mV higher. The photoelectrochemical tests revealed that the complexation of the conjugated polymer P<sub>OS</sub> turned its intrinsically electron-accepting (p-type) properties into an electron-donor (n-type) with photocurrent responses ten times higher than the organic photoelectrode. Overpotential ; Catalysis ; Platinum ; Inorganic chemistry ; Electrochemistry ; Conjugated system ; Photocurrent ; Materials science ; Electrode ; Aqueous solution ; Reversible hydrogen electrode ; Copper ; Noble metal ; Electrocatalyst ; Polymer ; Water splitting ; Chemistry ; Working electrode ; Organic chemistry ; Physical chemistry ; Photocatalysis ; Metallurgy Conducting polymers and applications ; Perovskite Materials and Applications ; Advanced battery technologies research
Authors: Carmine Coluccini | P. T. Anusha | Hsin-Yi Tiffany Chen | Sheng-Lun Liao | Ying Kuan Ko | Atsushi Yabushita | Chih‐Wei Luo | Yoke Mooi Ng | Yit Lung Khung
Source: Scientific Reports (article, 2019-09-04)
Field: Chemistry — Physical and Theoretical Chemistry

Tuning of the Electro-Optical Properties of Tetraphenylcyclopentadienone via Substitution of Oxygen with Sterically-Hindered Electron Withdrawing Groups In this report, the substitution of the oxygen group (=O) of Tetraphenylcyclopentadienone with =CR<sub>2</sub> group (R = methyl ester or nitrile) was found to have tuned the electro-optical properties of the molecule. Although both groups are electrons withdrawing in nature, their absorption from UV-vis spectra analysis was observed to have been blue-shifted by methyl ester substitution and red-shifted by nitrile substitution. Interestingly, these substitutions helped to enhance the overall intensity of emission, especially in the context of methyl ester substitution whereby the emission was significantly boosted at higher concentrations due to hypothesized restrictions of intramolecular motions. These observations were explained through detailed descriptions of the electron withdrawing capability and steric properties of the substituents on the basis of density functional theory calculations. Steric effects ; Polar effect ; Nitrile ; Context (archaeology) ; Intramolecular force ; Chemistry ; Substitution (logic) ; Density functional theory ; Molecule ; Oxygen ; Photochemistry ; Stereochemistry ; Computational chemistry ; Organic chemistry Photochemistry and Electron Transfer Studies ; Organic Light-Emitting Diodes Research ; Luminescence and Fluorescent Materials
Authors: Lajos Nagy | Miklós Nagy | Bence Vadkerti | Lajos Daróczi | György Deák | Miklós Zsuga | Sándor Kéki
Source: Polymers (article, 2019-05-07)
Field: Materials Science — Polymers and Plastics

Designed Polyurethanes for Potential Biomedical and Pharmaceutical Applications: Novel Synthetic Strategy for Preparing Sucrose Containing Biocompatible and Biodegradable Polyurethane Networks In this paper the preparation and detailed characterization of designed polyurethanes (SPURs) are reported for potential biological, biomedical and/or pharmaceutical applications. Importantly, in order to fulfill these goals all reactants and solvents used were selected according to the proposal of EUR-8 Pharmacopoeia. For the synthesis, a novel strategy was introduced and elaborated. A series of SPUR samples was prepared from poly(ε-caprolactone)-diol, 1,6-hexamethylene diisocyanate and sucrose as a chain extender/crosslinking agent to obtain sucrose containing polyurethanes. In addition, the mol ratios of the sucrose were varied within an order of magnitude. The prepolymers and the products of the syntheses were investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and infrared spectroscopy (IR), respectively. It was found that the reactivity of the eight free hydroxyl groups of sucrose are different, and after curing the SPUR samples at 60 °C no free isocyanate groups can be observed. Furthermore, swelling experiments performed with various solvents of different polarities revealed that the highest degree of swelling took place in dimethyl-sulfoxide. However, low degrees of swelling were recognized in water and hexane. It is important to note that the gel contents were around 90% in all cases, which demonstrate that the crosslinking was almost complete. In addition, the kinetics of swelling were also evaluated and successfully modeled. The crosslink densities were calculated from the data of the swelling experiments by means of the Flory-Rehner equation. Unexpectedly, it was found that the crosslink density decreased with the increasing sucrose content also in line with the results obtained by relaxation modulus experiments and dynamic mechanical analysis (DMA). The Tg and Tm of SPUR samples, determined from DSC and DMA measurements, were around -57 °C and 27 °C, respectively. According to the mechanical tests the SPUR samples showed high elongation at break values, i.e., high flexibilities. Furthermore, the stress-strain curves were also modeled and discussed. Polyurethane ; Swelling ; Hexamethylene diisocyanate ; Isocyanate ; Polymer chemistry ; Materials science ; Fourier transform infrared spectroscopy ; Solubility ; Dimethyl sulfoxide ; Kinetics ; Chemical engineering ; Curing (chemistry) ; Chemistry ; Organic chemistry ; Composite material Polymer composites and self-healing ; biodegradable polymer synthesis and properties ; Electrospun Nanofibers in Biomedical Applications
Authors: Francesco Rossi | Eng Huat Khoo | Xiaodi Su | Nguyễn Thị Kim Thanh
Source: ACS Applied Bio Materials (article, 2019-12-19)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Study of the Effect of Anisotropic Gold Nanoparticles on Plasmonic Coupling with a Photosensitizer for Antimicrobial Film Development of antimicrobial surfaces for sterilization is much needed to avoid the spreading of drug resistant bacteria. Light can activate antimicrobial surfaces by an interaction between nanoparticles and a photosensitizer dye to produce a steady and efficient killing of bacteria. The film studied in this work contains gold nanorods (AuNRs) of 32 nm length and 16 nm diameter and gold nanostars (AuNSs) of 50 nm of diameter, in combination with crystal violet (CV) dye. The surface plasmon resonance (SPR) of the nanoparticles used in the film was mathematically simulated and characterized to understand different SPR between the particles. Their effects on plasmonic coupling with the dye, and thus the production of reactive oxygen species (ROS) and consequently the activity of the film against bacteria, were studied. The films showed great antimicrobial activity against Gram-negative bacteria (<i>E. coli</i>) in 4 h of light exposure; when modified with AuNSs, it could kill <i>E. coli</i> with 5 orders of magnitude (5-log), and the one modified with AuNRs could kill with 4 order of magnitude (4-log), while maintaining partial activity against Gram-positive bacteria (<i>S. aureus</i>), i.e. being able to kill with 2.5 orders of magnitude by the film containing AuNSs and 3 orders of magnitude by those containing AuNRs. The differential response of Gram-negative and Gram-positive bacteria to the ROS generated by the films would allow a more targeted approach for specific bacterial species, for example, surfaces of bedpans or common contact surfaces (handles, handrails, etc.) that are contaminated principally by Gram-negative or Gram-positive bacteria, respectively. Surface plasmon resonance ; Photosensitizer ; Antimicrobial ; Colloidal gold ; Nanorod ; Bacteria ; Nanoparticle ; Materials science ; Nanotechnology ; Gram-negative bacteria ; Plasmon ; Chemistry ; Photochemistry ; Escherichia coli ; Optoelectronics ; Organic chemistry ; Biology ; Biochemistry Gold and Silver Nanoparticles Synthesis and Applications ; Nanoparticles: synthesis and applications ; Biosensors and Analytical Detection
Authors: Jinyang Zhang | Stuart Ferrie | Song Zhang | Yan B. Vogel | Chandramalika R. Peiris | Nadim Darwish | Simone Ciampi
Source: ACS Applied Nano Materials (article, 2019-10-28)
Field: Materials Science — Polymers and Plastics

Single-Electrode Electrochemistry: Chemically Engineering Surface Adhesion and Hardness To Maximize Redox Work Extracted from Tribocharged Silicon Recent research has demonstrated that heterogeneous charge-transfer reactions are not restricted to conductors and that electrochemical reactions can occur on the surface of statically charged insulators. However, the exact mechanism by which insulators gain and lose electrical charges remains controversial. Herein we have studied quantitatively the reduction of silver ions on intrinsic amorphous silicon surfaces that are statically charged by contact against plastic polymers. We have quantified the magnitude of the redox work done by the tribocharged silicon surface as a function of its adhesion and hardness, with these two variables being tuned using covalent Si—C monolayer chemistries. We observed that metallic particles grow preferentially over surfaces that are relatively soft (low DMT modulus) and highly adhesive, hence indirectly proving that the triboelectrification of an insulator–insulator dynamic contact is caused by the exchange of ionic fragments, rather than by the movement of free electrons. This work clarifies the origin of triboelectricity, devises a surface-chemistry method to maximize tribocharging with immediate scope in single-electrode electrochemistry, and describes a concept potentially suitable for the mask-free and bias-free patterning of metal nanoparticles on photoconductors. Triboelectric effect ; Contact electrification ; Materials science ; Silicon ; Ionic bonding ; Redox ; Nanotechnology ; Chemical physics ; Electrode ; Monolayer ; Electrochemistry ; Adhesion ; Work function ; Surface engineering ; Chemistry ; Composite material ; Ion ; Optoelectronics ; Physical chemistry ; Organic chemistry Conducting polymers and applications ; Molecular Junctions and Nanostructures ; Electrochemical Analysis and Applications
Authors: Aaron Mailman | Craig M. Robertson | Stephen M. Winter | Paul A. Dube | Richard T. Oakley
Source: Inorganic Chemistry (article, 2019-04-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

The Importance of Electronic Dimensionality in Multiorbital Radical Conductors The exceptional performance of oxobenzene-bridged bis-1,2,3-dithiazolyls 6 as single-component neutral radical conductors arises from the presence of a low-lying π-lowest unoccupied molecular orbital, which reduces the potential barrier to charge transport and increases the kinetic stabilization energy of the metallic state. As part of ongoing efforts to modify the solid-state structures and transport properties of these so-called multiorbital materials, we report the preparation and characterization of the acetoxy, methoxy, and thiomethyl derivatives 6 (R = OAc, OMe, SMe). The crystal structures are based on ribbonlike arrays of radicals laced together by S···N' and S···O' secondary bonding interactions. The steric and electronic effects of the exocyclic ligands varies, affording one-dimensional (1D) π-stacked radicals for R = OAc, 1D cofacial dimer π-stacks for R = SMe, and a pseudo two-dimensional (2D) brick-wall arrangement for R = OMe. Variable-temperature magnetic and conductivity measurements reveal strong antiferromagnetic interactions and Mott insulating behavior for the two radical-based structures (R = OAc, OMe), with lower room-temperature conductivities (σ<sub>RT</sub> ≈ 1 × 10<sup>-4</sup> and ∼1 × 10<sup>-3</sup> S cm<sup>-1</sup>, respectively) and higher thermal activation energies ( E<sub>act</sub> = 0.24 and 0.21 eV, respectively) than found for the ideal 2D brick-wall structure of 6 (R = F), where σ<sub>RT</sub> ≈ 1 × 10<sup>-2</sup> S cm<sup>-1</sup> and E<sub>act</sub> = 0.10 eV. The performance of R = OMe, OAc relative to that of R = F, is consistent with the results of density functional theory band electronic structure calculations, which indicate a lower kinetic stabilization energy of the putative metallic state arising from their reduced electronic dimensionality. Chemistry ; Steric effects ; Radical ; Antiferromagnetism ; Kinetic energy ; Dimer ; Crystallography ; Electronic structure ; Density functional theory ; Stereochemistry ; Computational chemistry ; Condensed matter physics ; Organic chemistry Organic and Molecular Conductors Research ; Magnetism in coordination complexes ; Organic Light-Emitting Diodes Research
Authors: James Taban Abdalla | Jinzhong Wang | Dongbo Wang
Source: Crystals (article, 2019-12-06)
Field: Materials Science — Materials Chemistry

Effect of Ag/rGO on the Optical Properties of Plasmon-Modified SnO2 Composite and Its Application in Self-Powered UV Photodetector A facile hydrothermal method was employed to synthesize silver–reduced graphene oxide (Ag/rGO) plasmon-modified SnO2 composite, by incorporating Ag–reduced graphene oxide (Ag/rGO) into SnO2 nanorods as a photoanode for assembling a self-powered ultraviolet photodetector (UVPD). The as-synthesized samples were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and UV visible spectrophotometer. The as-prepared Ag/rGO films show enhanced light absorption attributed to the localized surface plasmon resonance (LSPR). The optimized 1.0 wt.% Ag/rGO incorporated into SnO2-based UVPD exhibits a significant photocurrent response due to the enhanced absorption light and effective suppression of charge recombination. This UVPD demonstrates a high performance, with photocurrent density reaching 0.29 mAcm−2 compared to the SnO2-based device with 0.16 mAcm−2. This device also exhibits a high on:off ratio of 195 and fast response time, which are superior to that of the free-modified one. In addition, the UVPD based on plasmon-modified SnO2 photoanode treated with TiCl4-aqueous solution has attained a higher photocurrent with a maximum value reaching 5.4 mAcm−2, making this device favorable in ultraviolet detection. Photocurrent ; Materials science ; Surface plasmon resonance ; Nanorod ; Graphene ; Scanning electron microscope ; Photodetector ; Raman spectroscopy ; Ultraviolet ; Plasmon ; Absorption (acoustics) ; Optoelectronics ; Visible spectrum ; Analytical Chemistry (journal) ; Nanotechnology ; Nanoparticle ; Optics ; Chemistry ; Composite material ZnO doping and properties ; Gas Sensing Nanomaterials and Sensors ; Ga2O3 and related materials
Authors: Rebecka Andersson | Cecilia Safari | Petra Båth | Robert Bosman | Anastasya Shilova | Peter Dahl | Swagatha Ghosh | Andreas Dunge | Rasmus K. Jensen | Jie Nan | Robert L. Shoeman | Marco Kloos | R. Bruce Doak | U. Müeller | Richard Neutze | Gisela Brändén
Source: Acta Crystallographica Section D Structural Biology (article, 2019-10-01)
Field: Materials Science — Materials Chemistry

Well-based crystallization of lipidic cubic phase microcrystals for serial X-ray crystallography experiments Serial crystallography is having an increasing impact on structural biology. This emerging technique opens up new possibilities for studying protein structures at room temperature and investigating structural dynamics using time-resolved X-ray diffraction. A limitation of the method is the intrinsic need for large quantities of well ordered micrometre-sized crystals. Here, a method is presented to screen for conditions that produce microcrystals of membrane proteins in the lipidic cubic phase using a well-based crystallization approach. A key advantage over earlier approaches is that the progress of crystal formation can be easily monitored without interrupting the crystallization process. In addition, the protocol can be scaled up to efficiently produce large quantities of crystals for serial crystallography experiments. Using the well-based crystallization methodology, novel conditions for the growth of showers of microcrystals of three different membrane proteins have been developed. Diffraction data are also presented from the first user serial crystallography experiment performed at MAX IV Laboratory. Crystallization ; Diffraction ; Crystallography ; Protein crystallization ; X-ray crystallography ; Phase (matter) ; Materials science ; Crystal (programming language) ; Chemical physics ; Chemistry ; Computer science ; Physics ; Optics Enzyme Structure and Function ; Protein Structure and Dynamics ; Plant biochemistry and biosynthesis
Authors: Nils Demazy | Cian Cummins | Karim Aissou | Guillaume Fleury
Source: Advanced Materials Interfaces (article, 2019-12-29)
Field: Materials Science — Materials Chemistry

Non‐Native Block Copolymer Thin Film Nanostructures Derived from Iterative Self‐Assembly Processes Abstract Nanostructured block copolymer (BCP) thin films constitute an elegant tool to generate complex periodic patterns with periodicities ranging from a few nanometers to hundreds of nanometers. Such well‐organized nanostructures are foreseen to enable next‐generation nanofabrication research with potent applications in the design of functional materials in biology, optics or microelectronics. This valuable platform is, however, limited by the geometric features attainable from diblock copolymer architectures considering the thermodynamic driving force leaning toward the formation of structures minimizing the interface between the blocks. Therefore, strategies to enrich the variety of structures obtained by BCP self‐assembly processes are gaining momentum and this progress report reviews the opportunities inherent to iterative BCP self‐assembly by considering the emerging strategies for the generation of “non‐native” morphologies. Microelectronics ; Materials science ; Nanotechnology ; Copolymer ; Nanostructure ; Nanometre ; Self-assembly ; Nanoscopic scale ; Nanolithography ; Block (permutation group theory) ; Thin film ; Fabrication ; Polymer Block Copolymer Self-Assembly ; Advanced Polymer Synthesis and Characterization ; Polymer Surface Interaction Studies
Authors: Lukáš Chrást | Katsiaryna Tratsiak | Joan Planas-Iglesias | Lukáš Daniel | Tatyana Prudniková | Jan Brezovský | David Bednář | Ivana Kutá Smatanová | Radka Chaloupková | Jiřı́ Damborský
Source: Microorganisms (article, 2019-10-28)
Field: Materials Science — Materials Chemistry

Deciphering the Structural Basis of High Thermostability of Dehalogenase from Psychrophilic Bacterium Marinobacter sp. ELB17 Haloalkane dehalogenases are enzymes with a broad application potential in biocatalysis, bioremediation, biosensing and cell imaging. The new haloalkane dehalogenase DmxA originating from the psychrophilic bacterium <i>Marinobacter</i> sp. ELB17 surprisingly possesses the highest thermal stability (apparent melting temperature <i>T</i><sub>m,app</sub> = 65.9 °C) of all biochemically characterized wild type haloalkane dehalogenases belonging to subfamily II. The enzyme was successfully expressed and its crystal structure was solved at 1.45 Å resolution. DmxA structure contains several features distinct from known members of haloalkane dehalogenase family: (i) a unique composition of catalytic residues; (ii) a dimeric state mediated by a disulfide bridge; and (iii) narrow tunnels connecting the enzyme active site with the surrounding solvent. The importance of narrow tunnels in such paradoxically high stability of DmxA enzyme was confirmed by computational protein design and mutagenesis experiments. Thermostability ; Psychrophile ; Dehalogenase ; Thermophile ; Biocatalysis ; Chemistry ; Enzyme ; Active site ; Biochemistry ; Stereochemistry ; Biology ; Catalysis Enzyme Structure and Function ; Microbial bioremediation and biosurfactants ; Microbial metabolism and enzyme function