jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Samuel Guieu | Francisco Cardona | João Rocha | Artur M. S. Silva
Source: Chemistry - A European Journal (article, 2018-09-02)
Field: Materials Science — Materials Chemistry

Tunable Color of Aggregation‐Induced Emission Enhancement in a Family of Hydrogen‐Bonded Azines and Schiff Bases A simple synthesis strategy afforded a family of hydrogen-bonded azines and Schiff-bases. Although in dilute solution these dyes are faint light emitters, all exhibit bright luminescence upon aggregation. Changing the peripheral substituents from electron donating to electron withdrawing allows emission fine-tuning in a range from bluish-green to orange-red. The crystal structures of the materials reveal that the restriction of intramolecular rotations is the main mechanism for the aggregation-induced emission enhancement properties. Intramolecular force ; Aggregation-induced emission ; Photochemistry ; Luminescence ; Hydrogen bond ; Electron ; Materials science ; Orange (colour) ; Crystal structure ; Chemistry ; Crystallography ; Fluorescence ; Molecule ; Organic chemistry ; Optoelectronics ; Optics Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research ; Molecular Sensors and Ion Detection
Authors: Simone Famiani | Alec P. LaGrow | Maximilian O. Besenhard | Shinya Maenosono | Nguyễn Thị Kim Thanh
Source: Chemistry of Materials (article, 2018-11-20)
Field: Materials Science — Biomaterials

Synthesis of Fine-Tuning Highly Magnetic Fe@Fe<sub><i>x</i></sub>O<sub><i>y</i></sub> Nanoparticles through Continuous Injection and a Study of Magnetic Hyperthermia Core@shell Fe@FexOy nanoparticles (NPs) have the potential to be promising tools for many applications, thanks to their combination of an iron core, with a high magnetic moment and an iron oxide shell which could protect the core from oxidation. However, the deterioration of NPs structure can lead to the shrinking of the core and the hollowing of the structure, diminishing the magnetic properties. The ability to retain the iron core under biomedically compatible conditions is desirable for many applications. In this paper, we have developed a synthetic method to produce core@shell α-Fe@FexOy NPs with tunable sizes and evaluated the retention of the stable magnetic α-Fe core upon exposure to air and after ligand exchange and its resulting effect on the magnetic hyperthermia. In particular, using a continuous injection of the precursor, we were able to finely tune the final size of the core@shell NPs producing four samples with average sizes of 12, 15, 18, and 20 nm. The structural properties of the particles were studied, and while the size increases, the chemical stability of the iron core is enhanced, and the magnetic properties improved accordingly. Particles larger than 20 nm were shown to be prone to aggregation, resulting in an abrupt increase of the particle size distribution. Two samples with high magnetization saturation value and low polydispersity, 15 and 18 nm, were transferred in water using a dopamine-functionalized poly(isobutylene-alt-maleic anhydride) polymer, resulting in colloidal stability over a wide range of pH and ionic strength comparable to physiological conditions. We found that the 18 nm particles retain their chemical properties over 2 months, with less oxidation of the Fe core; this results in a specific absorption rate (SAR) value of 660 W g–1 and intrinsic loss power (ILP) of 3.6 nHm2 kg–1, while the 15 nm NPs resulted in the reduction of their properties due to oxidation of the core. Nanoparticle ; Dispersity ; Materials science ; Magnetic nanoparticles ; Magnetic hyperthermia ; Iron oxide ; Iron oxide nanoparticles ; Chemical engineering ; Magnetic core ; Particle size ; Magnetization ; Saturation (graph theory) ; Ionic strength ; Colloid ; Polymer ; Nanotechnology ; Chemistry ; Polymer chemistry ; Magnetic field ; Composite material ; Physical chemistry Nanoparticle-Based Drug Delivery ; Iron oxide chemistry and applications ; Characterization and Applications of Magnetic Nanoparticles
Authors: Qi Qiao | Chang Liu | Wei Gao | Liangliang Huang
Source: Carbon (article, 2018-11-23)
Field: Materials Science — Materials Chemistry

Graphene oxide model with desirable structural and chemical properties Graphene ; Vacancy defect ; Curvature ; Materials science ; Oxide ; Work (physics) ; X-ray photoelectron spectroscopy ; Molecular dynamics ; Chemical physics ; Fourier transform infrared spectroscopy ; Spectroscopy ; Nanotechnology ; Chemical engineering ; Computational chemistry ; Optics ; Chemistry ; Crystallography ; Physics ; Geometry ; Thermodynamics Graphene research and applications ; Graphene and Nanomaterials Applications ; Advanced Photocatalysis Techniques
Authors: Sabrina Engel | Nadja Möller | Lucas Stricker | Martin Peterlechner | Bart Jan Ravoo
Source: Small (article, 2018-03-24)
Field: Materials Science — Materials Chemistry

A Modular System for the Design of Stimuli‐Responsive Multifunctional Nanoparticle Aggregates by Use of Host–Guest Chemistry A self-assembly approach for the design of multifunctional nanomaterials consisting of different nanoparticles (gold, iron oxide, and lanthanide-doped LiYF<sub>4</sub> ) is developed. This modular system takes advantage of the light-responsive supramolecular host-guest chemistry of β-cyclodextrin and arylazopyrazole, which enables the dynamic and reversible self-assembly of particles to spherical nanoparticle aggregates in aqueous solution. Due to the magnetic iron oxide nanoparticles, the aggregates can be manipulated by an external magnetic field leading to the formation of linear structures. As a result of the integration of upconversion nanoparticles, the aggregates are additionally responsive to near-infrared light and can be redispersed by use of the upconversion effect. By varying the nanoparticle and linker concentrations the composition, size, shape, and properties of the multifunctional nanoparticle aggregates can be fine-tuned. Nanoparticle ; Nanomaterials ; Lanthanide ; Nanotechnology ; Iron oxide nanoparticles ; Aqueous solution ; Supramolecular chemistry ; Materials science ; Photon upconversion ; Self-assembly ; Magnetic nanoparticles ; Chemistry ; Doping ; Molecule ; Organic chemistry ; Optoelectronics ; Ion Nanocluster Synthesis and Applications ; Pickering emulsions and particle stabilization ; Quantum Dots Synthesis And Properties
Authors: Siew Yee Lim | Cheryl Suwen Law | Marijana Marković | Jason K. Kirby | Andrew D. Abell | Abel Santos
Source: ACS Applied Materials & Interfaces (article, 2018-06-25)
Field: Materials Science — Materials Chemistry

Engineering the Slow Photon Effect in Photoactive Nanoporous Anodic Alumina Gradient-Index Filters for Photocatalysis In this study, we explore for the first time the capabilities of nanoporous anodic alumina gradient-index filters (NAA-GIFs) functionalized with titanium dioxide (TiO<sub>2</sub>) photoactive layers to enhance photon-to-electron conversion rates and improve the efficiency of photocatalytic reactions by "slow photon" effect. A set of NAA-GIFs was fabricated by sinusoidal pulse anodization, in which a systematic modification of various anodization parameters (i.e., pore widening time, anodization period, and anodization time) enables the fine-tuning of the photonic stopband (PSB) of these nanoporous photonic crystals (PCs) across the spectral regions. The surface of NAA-GIFs was chemically modified with photoactive layers of TiO<sub>2</sub> to create a composite photoactive material with precisely engineered optical properties. The photocatalytic performance of TiO<sub>2</sub>-functionalized NAA-GIFs was assessed by studying the photodegradation of three model organic dyes (i.e., methyl orange, Rhodamine B, and methylene blue) with well-defined absorption bands across different spectral regions under simulated irradiation conditions. Our study demonstrates that when the edges of characteristic PSB of TiO<sub>2</sub>-modified NAA-GIFs are completely or partially aligned with the absorption band of the organic dyes, the photodegradation rate is enhanced due to "slow photon" effect. A rational design of the photocatalyst material with respect to the organic dye is demonstrated to be optimal to speed up photocatalytic reactions by an efficient management of photons from high-irradiance spectral regions. This provides new opportunities to develop high-performing photocatalytic materials for efficient photocatalysis with broad applicability. Materials science ; Photocatalysis ; Nanoporous ; Photodegradation ; Methyl orange ; Anodizing ; Titanium dioxide ; Photonics ; Photochemistry ; Chemical engineering ; Optoelectronics ; Nanotechnology ; Composite material ; Organic chemistry ; Catalysis ; Aluminium Anodic Oxide Films and Nanostructures ; Photonic Crystals and Applications ; Optical Coatings and Gratings
Authors: Shuai Zhang | Lei Gao | Aisheng Song | Xiaohu Zheng | Quanzhou Yao | Tianbao Ma | Zengfeng Di | Xi‐Qiao Feng | Qunyang Li
Source: Nano Letters (article, 2018-08-30)
Field: Materials Science — Materials Chemistry

Tuning Local Electrical Conductivity via Fine Atomic Scale Structures of Two-Dimensional Interfaces Two-dimensional (2D) materials have seen a broad range of applications in electronic and optoelectronic applications; however, full realization of this potential hitherto largely hinges on the quality and performance of the electrical contacts formed between 2D materials and their surrounding metals/semiconductors. Despite the progress in revealing the charge injecting mechanisms and enhancing electrical conductance using various interfacial treatments, how the microstructure of contact interfaces affects local electrical conductivity is still very limited. Here, using conductive atomic force microscopy (c-AFM), for the first time, we directly confirm the conjecture that the electrical conductivity of physisorbed 2D material-metal/semiconductor interfaces is determined by the local electronic charge transfer. Using lattice-resolved conductivity mapping and first-principles calculations, we demonstrate that the electronic charge transfer, thereby electrical conductivity, can be fine-tuned by the topological defects of 2D materials and the atomic stacking with respect to the substrate. Our finding provides a novel route to engineer the electrical contact properties by exploiting fine atomic interactions; in the meantime, it also suggests a convenient and nondestructive means of probing subtle interactions along 2D heterogeneous interfaces. Materials science ; Semiconductor ; Conductivity ; Stacking ; Electrical resistivity and conductivity ; Atomic units ; Conductive atomic force microscopy ; Electrical contacts ; Electrical conductor ; Nanotechnology ; Optoelectronics ; Chemical physics ; Atomic force microscopy ; Chemistry ; Composite material ; Physics Graphene research and applications ; 2D Materials and Applications ; Molecular Junctions and Nanostructures
Authors: Zuzana Vajglová | Narendra Kumar | Markus Peurla | Janne Peltonen | Ivo Heinmaa | Dmitry Yu. Murzin
Source: Catalysis Science & Technology (article, 2018-01-01)
Field: Chemistry — Inorganic Chemistry

Synthesis and physicochemical characterization of beta zeolite–bentonite composite materials for shaped catalysts Composite materials for shaped catalysts were prepared from three commercial beta zeolites using bentonite as an aluminosilicate clay binder. Bentonite ; Aluminosilicate ; Catalysis ; Zeolite ; Composite number ; Characterization (materials science) ; Chemical engineering ; Materials science ; BETA (programming language) ; Chemistry ; Composite material ; Organic chemistry ; Nanotechnology ; Engineering Zeolite Catalysis and Synthesis ; Mesoporous Materials and Catalysis ; Chemical Synthesis and Characterization
Authors: Raffaele Cheula | Aloysius Soon | Matteo Maestri
Source: Catalysis Science & Technology (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Prediction of morphological changes of catalyst materials under reaction conditions by combined <i>ab initio</i> thermodynamics and microkinetic modelling In this article, we couple microkinetic modelling, <i>ab initio</i> thermodynamics and Wulff-Kaishew construction to describe the structural variation of catalyst materials as a function of the chemical potential in the reactor. We focus specifically on experiments of catalytic partial oxidation (CPO) of methane on Rh/α-Al<sub>2</sub>O<sub>3</sub>. We employ a detailed structureless microkinetic model to calculate the profiles of the gaseous species molar fractions along the reactor coordinate and to select the most abundant reaction intermediates (MARIs) populating the catalyst surfaces in different zones of the reactor. Then, we calculate the most stable bulk and surface structures of the catalyst under different conditions of the reaction environment with density functional theory (DFT) calculations and <i>ab initio</i> thermodynamics, considering the presence of the MARIs on the catalyst surface in thermodynamic equilibrium with the partial pressures of their reservoirs in the gas phase surrounding the catalyst. Finally, we exploit the Wulff-Kaishew construction method to estimate the three-dimensional shape of the catalyst nanoparticles and the distribution of the active sites along the reactor coordinate. We find that the catalyst drastically modifies its morphology during CPO reaction by undergoing phase transition, in agreement with spectroscopy studies reported in the literature. The framework is also successfully applied for the analysis and interpretation of chemisorption experiments for catalyst characterization. These results demonstrate the crucial importance of rigorously accounting for the structural effect in microkinetic modeling simulations and pave the way towards the development of structure-dependent microkinetic analysis of catalytic processes. Catalysis ; Thermodynamics ; Ab initio ; Chemistry ; Materials science ; Computational chemistry ; Organic chemistry ; Physics Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions ; Catalysis and Hydrodesulfurization Studies
Authors: Nora Bloise | Emanuele Berardi | Chiara Gualandi | Elisa Zaghi | Matteo Gigli | Robin Duelen | Gabriele Ceccarelli | Emanuela Elsa Cortesi | Domiziana Costamagna | Giovanna Bruni | Nadia Lotti | Maria Letizia Focarete | Livia Visai | Maurilio Sampaolesi
Source: International Journal of Molecular Sciences (article, 2018-10-17)
Field: Materials Science — Biomaterials

Ether-Oxygen Containing Electrospun Microfibrous and Sub-Microfibrous Scaffolds Based on Poly(butylene 1,4-cyclohexanedicarboxylate) for Skeletal Muscle Tissue Engineering We report the study of novel biodegradable electrospun scaffolds from poly(butylene 1,4-cyclohexandicarboxylate-<i>co</i>-triethylene cyclohexanedicarboxylate) (P(BCE-<i>co</i>-TECE)) as support for in vitro and in vivo muscle tissue regeneration. We demonstrate that chemical composition, i.e., the amount of TECE co-units (constituted of polyethylene glycol-like moieties), and fibre morphology, i.e., aligned microfibrous or sub-microfibrous scaffolds, are crucial in determining the material biocompatibility. Indeed, the presence of ether linkages influences surface wettability, mechanical properties, hydrolytic degradation rate, and density of cell anchoring points of the studied materials. On the other hand, electrospun scaffolds improve cell adhesion, proliferation, and differentiation by favouring cell alignment along fibre direction (fibre morphology), also allowing for better cell infiltration and oxygen and nutrient diffusion (fibre size). Overall, C2C12 myogenic cells highly differentiated into mature myotubes when cultured on microfibres realised with the copolymer richest in TECE co-units (micro-P73 mat). Lastly, when transplanted in the tibialis anterior muscles of healthy, injured, or dystrophic mice, micro-P73 mat appeared highly vascularised, colonised by murine cells and perfectly integrated with host muscles, thus confirming the suitability of P(BCE-<i>co</i>-TECE) scaffolds as substrates for skeletal muscle tissue engineering. Biocompatibility ; C2C12 ; Myogenesis ; Tissue engineering ; Skeletal muscle ; Chemistry ; Materials science ; In vivo ; Regeneration (biology) ; Copolymer ; Mesenchymal stem cell ; Cell adhesion ; Biophysics ; Biomedical engineering ; Cell ; In vitro ; Polymer ; Anatomy ; Cell biology ; Biochemistry ; Organic chemistry ; Biology Electrospun Nanofibers in Biomedical Applications ; biodegradable polymer synthesis and properties ; Graphene and Nanomaterials Applications
Authors: Hans von Berlepsch | Bala N. S. Thota | Monika Wyszogrodzka | Sacha De Carlo | Rainer Haag | Christoph Böttcher
Source: Soft Matter (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles A series of novel non-ionic amphiphiles with dendritic oligoglycerol head groups of different generations ([G1]-[G3]) and lipophilic/fluorophilic tail segments, comprising single or double tail alkyl chains, C8F17-perfluoro rod segments as well as flexible spacer groups of different lengths were designed and synthesized. We expected that the differences in the size of the dendritic head groups in combination with perfluorinated segments would have an impact on the supramolecular structures formed in aqueous solution if compared with the hydrogenated analogues. Investigating the self-assembly behavior mainly by cryogenic transmission electron microscopy (cryo-TEM) and cryo-electron tomography (cryo-ET) we found as a new result the formation of perforated bilayer vesicles (stomatosomes) and bicontinuous network structures. Surprisingly, we have observed stomatosome formation by self-assembly of single component fluorinated dendritic amphiphiles. These assembly structures turned out to be extremely robust against harsh conditions, although there are strong indications that they represent non-equilibrium structures, which eventually transform into a bicontinuous cubic network structure of double diamond symmetry. In general, the molecular asymmetry of amphiphiles tuned by chemical design induced the expected trend from spherical micelles through worm-like micelles to perforated bilayers and three-dimensional network structures. Component (thermodynamics) ; Amphiphile ; Chemistry ; Nanotechnology ; Materials science ; Chemical engineering ; Organic chemistry ; Physics ; Copolymer ; Engineering ; Polymer ; Thermodynamics Surfactants and Colloidal Systems ; Dendrimers and Hyperbranched Polymers ; Advanced Polymer Synthesis and Characterization
Authors: Zina Vuluga | Mihai Cosmin Corobea | Cristina Elizetxea | Mario Ordóñez | Marius Ghiurea | Valentin Rădițoiu | Cristian Andi Nicolae | Dorel Florea | Michaela Iorga | Raluca Şomoghi | Bogdan Trică
Source: Polymers (article, 2018-07-25)
Field: Materials Science — Polymers and Plastics

Morphological and Tribological Properties of PMMA/Halloysite Nanocomposites From an environmental and cost-effective perspective, a number of research challenges can be found for electronics, household, but especially in the automotive polymer parts industry. Reducing synthesis steps, parts coating and painting, or other solvent-assisted processes, have been identified as major constrains for the existing technologies. Therefore, simple polymer processing routes (mixing, extrusion, injection moulding) were used for obtaining PMMA/HNT nanocomposites. By these techniques, an automotive-grade polymethylmethacrylate (PMMA) was modified with halloysite nanotubes (HNT) and an eco-friendly additive <i>N</i>,<i>N</i>'-ethylenebis(stearamide) (EBS) to improve nanomechanical properties involved in scratch resistance, mechanical properties (balance between tensile strength and impact resistance) without diminishing other properties. The relationship between morphological/structural (XRD, TEM, FTIR) and tribological (friction) properties of PMMA nanocomposites were investigated. A synergistic effect was found between HNT and EBS in the PMMA matrix. The synergy was attained by the phase distribution resulted from the selective interaction between partners and favourable processing conditions. Modification of HNT with EBS improved the dispersion of nanoparticles in the polymer matrix by increasing their interfacial compatibility through hydrogen bonding established by amide groups with aluminol groups. The increased interfacial adhesion further improved the nanocomposite scratch resistance. The PMMA/HNT-EBS nanocomposite had a lower coefficient of friction and lower scratch penetration depth than PMMA/HNT nanocomposite. Halloysite ; Tribology ; Nanocomposite ; Materials science ; Composite material Polymer Nanocomposites and Properties ; Tribology and Wear Analysis ; Lubricants and Their Additives
Authors: Taihong Liu | Xinglei Liu | Weina Wang | Zhipu Luo | Muqiong Liu | Shengli Zou | Cristina Sissa | Anna Painelli | Yuanwei Zhang | Mikas Vengris | Mykhailo V. Bondar | David J. Hagan | Eric W. Van Stryland | Yu Fang | Kevin D. Belfield
Source: The Journal of Physical Chemistry C (article, 2018-01-25)
Field: Materials Science — Materials Chemistry

Systematic Molecular Engineering of a Series of Aniline-Based Squaraine Dyes and Their Structure-Related Properties With the objective of developing new near-infrared fluorescent probes and understanding the effect molecular structure exerts on physical properties, a series of aniline-based squaraine dyes with different number and position of methoxy substituents adjacent to the squaraine core were synthesized and investigated. Using both computational and experimental methods, we found that the subtle changes of the number or position of the methoxy substituents influenced the twisting angle of the structure and led to significant variations in optical properties. Moreover, the methoxy substituent also affected aggregation behavior due to steric effects. The X-ray crystal structure of one of the key members of the series, SD-2a, clearly demonstrates the distortion between the four-membered squaraine core and the adjacent aniline ring due to methoxy substitution. Structure-related fast relaxation processes were investigated by femtosecond pump–probe experiments and transient absorption spectra. Quantum chemical calculations and essential state models were exploited to analyze the primary experimental results. The comprehensive investigation of structure-related properties of dihydroxylaniline-based squaraine dyes, with systematic substitution of OH by OCH3 functional groups, serves as a guide for the design of novel squaraine dyes for photonics applications. Aniline ; Chemistry ; Molecular engineering ; Steric effects ; Substituent ; Time-dependent density functional theory ; Ultrafast laser spectroscopy ; Relaxation (psychology) ; Photochemistry ; Computational chemistry ; Density functional theory ; Stereochemistry ; Organic chemistry ; Spectroscopy Photochromic and Fluorescence Chemistry ; Porphyrin and Phthalocyanine Chemistry ; Photochemistry and Electron Transfer Studies