jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Hong Yan | Jacqueline M. Börgers | Marc‐André Rose | Christoph Baeumer | Bongju Kim | Lei Jin | Regina Dittmann | Felix Gunkel
Source: Advanced Materials Interfaces (article, 2020-12-15)
Field: Materials Science — Materials Chemistry

Stoichiometry and Termination Control of LaAlO<sub>3</sub>/SrTiO<sub>3</sub> Bilayer Interfaces Abstract Driven by the interest in fundamental physics and potential applications in novel electronic devices, intense effort is devoted to integration of oxide‐based 2D electron gases (2DEGs) with other functional materials. As a classic model system, LaAlO 3 /SrTiO 3 (LAO/STO) has gained significant attentions. However, due to limitations in synthesis and high demands on the involved thin films, the formation of conductive interfaces between artificially grown STO and LAO thin films is an extreme challenge; oftentimes these interfaces remain insulating or show poor transport properties, which inhibits the development of all‐thin‐film devices. Here, by adopting high temperature growth to achieve step‐flow growth mode and fine‐tuning the laser fluence during pulsed laser deposition, high quality homoepitaxial STO thin films with sufficiently low point‐defect concentration and controllable surface termination are obtained. Fully metallic 2DEGs are then realized at interfaces between STO thin films and both crystalline and amorphous LAO overlayers. The observed slightly reduced mobility in the bilayer LAO/STO/STO structures as compared with single‐layer LAO/STO structures is related to residual defect formation during STO synthesis, yielding a disordered metallic oxide system. The results give prospect of multilayer interfaces potentially accessible in superlattice structures and provide a reliable starting point for back‐gated all‐thin‐film field‐effect devices. Materials science ; Stoichiometry ; Bilayer ; Condensed matter physics ; Crystallography ; Physical chemistry ; Physics ; Chemistry Electronic and Structural Properties of Oxides ; Magnetic and transport properties of perovskites and related materials ; Ferroelectric and Piezoelectric Materials
Authors: Martin Piesch | Manfred Scheer
Source: Organometallics (article, 2020-05-22)
Field: Chemistry — Inorganic Chemistry

Synthesis of a Heterobimetallic Arsenic Triple-Decker Complex and Its Fragmentation Chemistry The synthesis of the metastable triple-decker complex [(Cp*Fe)(Cp‴Co)(μ,η5:η4-As5)] (3) (Cp* = pentamethyl-cyclopentadienyl, Cp‴ = 1,2,4-tritertbutyl-cyclopentadienyl) is reported. 3 is sensitive toward thermal activation (and in solutions of acetonitrile), which converts 3 selectively into [(Cp*Fe)(Cp‴Co)(μ,η3:η3-As3)] (4) and [(Cp*Fe)2(Cp‴Co)2 (μ4,η4:η4:η4:η3-As11)] (5). Harsher thermal reaction conditions lead to a further fragmentation into [Cp*Fe(η5-As5)] (1b), [(Cp‴Co)2(μ,η2:η2-As2)2] (6), and [(Cp*Fe)2(Cp‴Co)(μ3,η2:η2:η2-As3)2] (7), which can be completed by longer reaction times or higher temperatures. The fragmentation was investigated by variable-temperature and time-dependent NMR spectroscopy, and a fine-tuning of the selectivity can be achieved by applying different reaction conditions. All compounds were fully characterized, and their electronic structures were elucidated by DFT calculations. Chemistry ; Cyclopentadienyl complex ; Acetonitrile ; Fragmentation (computing) ; Metastability ; Selectivity ; Arsenic ; Nuclear magnetic resonance spectroscopy ; Sandwich compound ; Stereochemistry ; Physical chemistry ; Inorganic chemistry ; Medicinal chemistry ; Crystallography ; X-ray crystallography ; Organic chemistry ; Catalysis Synthesis and characterization of novel inorganic/organometallic compounds ; Organometallic Complex Synthesis and Catalysis ; Coordination Chemistry and Organometallics
Authors: Eliška Procházková | Juraj Filo | Marek Cigáň | Ondřej Baszczyňski
Source: European Journal of Organic Chemistry (article, 2020-01-09)
Field: Materials Science — Materials Chemistry

Sterically‐Controlled Self‐Immolation in Phosphoramidate Linkers Triggered by Light Phosphoramidate prodrugs stand out for their applications as drug delivery systems. However, information on their activation remains limited to prodrug half‐live and metabolite structure, which hinders their development. Considering the lack of data on phosphoramidate self‐immolation, we studied light‐triggered self‐immolation of phosphoramidate‐based linkers bearing various amino acid arms by NMR spectroscopy with in situ irradiation, complemented with mathematical fitting, and by optical methods. By changing the alanine arm, we were able to systematically fine‐tune, slow down or speed up the cyclization rate. The cyclization rate of branched amino acid arms increased with the steric demands of their α‐substituents according to the Thorpe‐Ingold effect. The cyclization of β‐alanine and proline was very slow or did not proceed at all, but lactate may be a good alternative for the alanine arm because lactate exhibits a significantly slower cyclization rate than alanine (ca. 60 times). Overall, our study demonstrates that phosphoramidate self‐immolation strongly depends on the structure of the amino acid arm and on the conditions used (solvent, concentration and temperature), thereby providing a solid foundation for the rational design of new self‐immolative phosphoramidate systems with desired properties. Phosphoramidate ; Chemistry ; Steric effects ; Prodrug ; Alanine ; Stereochemistry ; Combinatorial chemistry ; Amino acid ; Biochemistry Photochromic and Fluorescence Chemistry ; RNA Interference and Gene Delivery ; Synthesis and Characterization of Heterocyclic Compounds
Authors: Jing Wang | Fabiana Lisco | David A. Hutt | Lewis C. R. Jones | Jake W. Bowers | Patrick Isherwood | Zhaoxia Zhou | Paul Conway
Source: Materials & Design (article, 2020-06-05)
Field: Materials Science — Materials Chemistry

Laser sintering and patterning of gallium-doped zinc oxide/indium-tin oxide nanoparticle films with tailorable electrical and optical properties Gallium-doped zinc oxide (GZO) and tin-doped indium oxide (ITO) nanoparticles (NPs) were combined to create bi-component suspensions for the drop-casting and CO2-laser sintering of transparent conducting oxide (TCO) thin films with significantly reduced ITO content. An aqueous dispersion of ITO NPs enabled the suspension of GZO NPs without surfactants. Transmission electron microscopy indicated the formation of high aspect-ratio segments of ITO NPs from the suspension through oriented attachment, that persisted in the deposited and sintered thin films to establish an efficient electrical percolating network within the less conductive GZO NP matrix. Rapid CO2-laser sintering under argon gas of approximately 800 nm thick NP films yielded resistivities of 7.34 × 10−3 Ω·cm and 116 Ω·cm for pure ITO and pure GZO respectively. However, a bi-component film with only 19.6 at.% indium (relative to zinc) achieved a resistivity of 3.21 × 10−1 Ω·cm. By changing the ITO content, the near-infrared transmittance could be adjusted between 13% and 82% and the optical bandgap energy between 3.93 and 3.33 eV, enabling fine-tuning of the properties. Finally, a fast and material/energy efficient processing route was demonstrated for the fabrication of a GZO-ITO circuit pattern using CO2-laser patterning of a mask and CO2-laser sintering of the NP films. Materials science ; Indium tin oxide ; Transparent conducting film ; Sintering ; Indium ; Doping ; Thin film ; Band gap ; Gallium ; Nanoparticle ; Pulsed laser deposition ; Laser ablation ; Optoelectronics ; Composite material ; Laser ; Nanotechnology ; Metallurgy ; Optics ZnO doping and properties ; Copper-based nanomaterials and applications ; Gas Sensing Nanomaterials and Sensors
Authors: Ben Schoenaers | Alessandra Leonhardt | Ankit Nalin Mehta | A. Stesmans | Daniele Chiappe | Inge Asselberghs | Iuliana Radu | Cedric Huyghebaert | Stefan De Gendt | Michel Houssa | V. V. Afanas’ev
Source: ECS Journal of Solid State Science and Technology (article, 2020-01-10)
Field: Materials Science — Materials Chemistry

Analysis of Transferred MoS<sub>2</sub> Layers Grown by MOCVD: Evidence of Mo Vacancy Related Defect Formation A low-temperature multi-frequency electron spin resonance (ESR) study has been carried out on 1, 3.5, and 6 layer thick MoS 2 films, grown by metal organic vapor deposition (MOCVD) and subsequently transferred on SiO 2 /Si. This reveals the observation of a previously unreported, nearly isotropic signal at g ≈ 1.9998 with corresponding spin center (spin S = ½) densities ranging from ∼6 × 10 8 cm −2 to ∼5 × 10 11 cm −2 . The ESR investigation is closely combined with an in-depth analysis by an assortment of other experimental techniques, including atomic force microscopy (AFM), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM), to ultimately result in the assignment of the ESR signal to a defect of intrinsic nature, most likely a Mo vacancy (V Mo ) related defect located at MoS 2 grain edges or boundaries. The oxidation of the 2D material at grain edges and boundaries combined with the applied water-based transfer procedure is demonstrated to play a crucial role in the generation of the newly observed defect, thus advising caution with the currently applied process method. The presented analysis, which combines a variety of experimental techniques, contributes to the fine-tuning of the CVD growth and transfer process of high-quality few-layer MoS 2 intended for next-generation nanoelectronic devices. Materials science ; X-ray photoelectron spectroscopy ; Metalorganic vapour phase epitaxy ; Chemical vapor deposition ; Transmission electron microscopy ; Vacancy defect ; Electron paramagnetic resonance ; Analytical Chemistry (journal) ; Grain boundary ; Layer (electronics) ; Spectroscopy ; Optoelectronics ; Crystallography ; Nanotechnology ; Nuclear magnetic resonance ; Metallurgy ; Chemistry ; Microstructure ; Physics 2D Materials and Applications ; MXene and MAX Phase Materials ; Perovskite Materials and Applications
Authors: Yue‐Biao Zhang | Qiaowei Li | Hexiang Deng
Source: Nano Research (article, 2020-11-28)
Field: Chemistry — Inorganic Chemistry

Reticular chemistry at the atomic, molecular, and framework scales Reticular connective tissue ; Nanotechnology ; Atomic units ; Chemistry ; Chemical physics ; Materials science ; Physics ; Medicine ; Quantum mechanics ; Pathology Metal-Organic Frameworks: Synthesis and Applications ; Covalent Organic Framework Applications ; Luminescence and Fluorescent Materials
Authors: Søren Leth Mejlsøe | Ashok Kakkar
Source: Molecules (review, 2020-09-02)
Field: Materials Science — Polymers and Plastics

Telodendrimers: Promising Architectural Polymers for Drug Delivery Architectural complexity has played a key role in enhancing the efficacy of nanocarriers for a variety of applications, including those in the biomedical field. With the continued evolution in designing macromolecules-based nanoparticles for drug delivery, the combination approach of using important features of linear polymers with dendrimers has offered an advantageous and viable platform. Such nanostructures, which are commonly referred to as telodendrimers, are hybrids of linear polymers covalently linked with different dendrimer generations and backbones. There is considerable variety in selection from widely studied linear polymers and dendrimers, which can help tune the overall composition of the resulting hybrid structures. This review highlights the advances in articulating syntheses of these macromolecules, and the contributions these are making in facilitating therapeutic administration. Limited progress has been made in the design and synthesis of these hybrid macromolecules, and it is through an understanding of their physicochemical properties and aqueous self-assembly that one can expect to fully exploit their potential in drug delivery. Dendrimer ; Nanocarriers ; Nanotechnology ; Drug delivery ; Macromolecule ; Linear polymer ; Polymer ; Variety (cybernetics) ; Polymer architecture ; Materials science ; Computer science ; Combinatorial chemistry ; Chemistry ; Organic chemistry ; Polymer chemistry Dendrimers and Hyperbranched Polymers ; Advanced Polymer Synthesis and Characterization ; Ferrocene Chemistry and Applications
Authors: Yuki Maeda | Takumi Yasuda | Kenta Matsuzaki | Yutaka Okazaki | Émilie Pouget | Reïko Oda | Atsushi Kitada | Kuniaki Murase | Guillaume Raffy | Dario M. Bassani | Kazuhiro Fukami
Source: Electrochemistry Communications (article, 2020-03-22)
Field: Materials Science — Polymers and Plastics

Common mechanism for helical nanotube formation by anodic polymerization and by cathodic deposition using helical pores on silicon electrodes We report that platinum-assisted chemical etching formed self-organized helical pores in silicon substrates can be utilized as platforms for the electrochemical production of nanohelices of conducting polymers (polypyrrole) and metals (gold). Surprisingly, the nanohelices thus created are tubes although the polymerization and deposition were carried out by anodic and cathodic reactions, respectively. Based on our results, we propose a common mechanism for the formation of tubular nanohelices by both anodic polymerization and cathodic deposition through the accumulation of reactants in microporous silicon which covers the wall surface of the helical pores. Microporous material ; Materials science ; Anode ; Silicon ; Deposition (geology) ; Cathodic protection ; Chemical engineering ; Electrochemistry ; Etching (microfabrication) ; Polymerization ; Polypyrrole ; Nanotechnology ; Polymer ; Electrode ; Chemistry ; Composite material ; Metallurgy ; Layer (electronics) ; Physical chemistry Conducting polymers and applications ; Molecular Junctions and Nanostructures ; Supercapacitor Materials and Fabrication
Authors: Jason M. Delente | Deivasigamani Umadevi | Kevin Byrne | Wolfgang Schmitt | Graeme W. Watson | Thorfinnur Gunnlaugsson | Sankarasekaran Shanmugaraju
Source: Supramolecular chemistry (article, 2020-09-01)
Field: Materials Science — Materials Chemistry

Hyper-crosslinked 4-amino-1,8-naphthalimide Tröger’s base containing pyridinium covalent organic polymer (COP) for discriminative fluorescent sensing of chemical explosives A new hyper-crosslinked 4-amino-1,8-naphthalimide Tröger’s base containing pyridinium covalent organic polymer, TBNap-COP, was synthesised and employed as a ‘turn-off’ fluorescent chemosensor for nitroaromatic explosives. TBNap-COP was synthesised in quantitative yield using a one-step nucleophilic substitution reaction between a dipyridyl scaffold (TBNap, bis-[N-(2-(pyridine-4-yl)ethyl)]-9,18-methano-1,8-naphthalimide-[b,f][1,5]diazocine) and 1,3,5-tris(bromomethyl)benzene by heating in DMF for 3 days. The formation and phase-purity of TBNap-COP were fully characterised by using various spectroscopic and microscopy analyses. The suspension of TBNap-COP in water showed strong fluorescence emission characteristics owing to the ‘push-pull’ based ICT transition and it was used as a fluorescent sensor for discriminative detection of nitroaromatic explosives. TBNap-COP displayed selective fluorescence quenching responses for phenolic-nitroaromatics, with particularly high sensitivity for picric acid which is a powerful secondary chemical explosive and a harmful environmental pollutant widely used in the dye industries. Chemistry ; Fluorescence ; Picric acid ; Pyridinium ; Covalent bond ; Nucleophilic substitution ; Polymer ; Photochemistry ; Benzoxazole ; Explosive material ; Organic chemistry Luminescence and Fluorescent Materials ; Covalent Organic Framework Applications ; Molecular Sensors and Ion Detection
Authors: João Restivo | O.S.G.P. Soares | M. Fernando R. Pereira
Source: Processes (article, 2020-10-22)
Field: Materials Science — Materials Chemistry

Processing Methods Used in the Fabrication of Macrostructures Containing 1D Carbon Nanomaterials for Catalysis A large number of methodologies for fabrication of 1D carbon nanomaterials have been developed in the past few years and are extensively described in the literature. However, for many applications, and in particular in catalysis, a translation of the materials to a macro-structured form is often required towards their use in practical operation conditions. This review intends to describe the available methods currently used for fabrication of such macro-structures, either already applied or with potential for application in the fabrication of macro-structured catalysts containing 1D carbon nanomaterials. A review of the processing methods used in the fabrication of macrostructures containing 1D sp2 hybridized carbon nanomaterials is presented. The carbon nanomaterials here discussed include single- and multi-walled carbon nanotubes, and several types of carbon nanofibers (fishbone, platelet, stacked cup, etc.). As the processing methods used in the fabrication of the macrostructures are generally very similar for any of the carbon nanotubes or nanofibers due to their similar chemical nature (constituted by stacked ordered graphene planes), the review aggregates all under the carbon nanofiber (CNF) moniker. The review is divided into methods where the CNFs are synthesized already in the form of a macrostructure (in situ methods) or where the CNFs are previously synthesized and then further processed into the desired macrostructures (ex situ methods). We highlight in particular the advantages of each approach, including a (non-exhaustive) description of methods commonly described for in situ and ex situ preparation of the catalytic macro-structures. The review proposes methods useful in the preparation of catalytic structures, and thus a number of techniques are left out which are used in the fabrication of CNF-containing structures with no exposure of the carbon materials to reactants due to, for example, complete coverage of the CNF. During the description of the methodologies, several different macrostructures are described. A brief overview of the potential applications of such structures in catalysis is also offered herein, together with a short description of the catalytic potential of CNFs in general. Nanotechnology ; Carbon nanotube ; Fabrication ; Nanomaterials ; Carbon nanofiber ; Materials science ; Carbon fibers ; Catalysis ; Graphene ; Composite number ; Composite material ; Chemistry ; Organic chemistry Graphene research and applications ; Carbon Nanotubes in Composites ; Supercapacitor Materials and Fabrication
Authors: Eduardo R. Cruz-Chú | Gonzalo Javier Villegas Rodríguez | Tobias Jäger | Luca Valentini | Nicola M. Pugno | Konstantinos Gkagkas | Frauke Gräter
Source: npj Computational Materials (article, 2020-10-12)
Field: Materials Science — Materials Chemistry

Mechanical characterization and induced crystallization in nanocomposites of thermoplastics and carbon nanotubes Abstract Nanocomposites built from polymers and carbon nanotubes (CNTs) are a promising class of materials. Computer modeling can provide nanoscale views of the polymer–CNT interface, which are much needed to foster the manufacturing and development of such materials. However, setting up periodic nanocomposite models is a challenging task. Here we propose a computational workflow based on Molecular Dynamics simulations. We demonstrate its capabilities and showcase its applications, focusing on two existing nanocomposite materials: polystyrene (PS) with CNT and polyether ether ketone with CNT. The models provide insights into the polymer crystallization inside CNTs. Furthermore, the PS+CNT nanocomposite models are mechanically tested and able to predict an enhancement in Young’s modulus due to the addition of highly dispersed CNTs. We accompany those results with experimental tests and provide a prediction model based on Dynamic Quantized Fracture Mechanics theory. Our study proposes representative simulations of polymer–CNT nanocomposites as promising tools to guide the rational design of this class of materials. Nanocomposite ; Carbon nanotube ; Materials science ; Characterization (materials science) ; Polymer ; Polymer nanocomposite ; Crystallization ; Polystyrene ; Composite material ; Nanoscopic scale ; Nanotechnology ; Chemical engineering Carbon Nanotubes in Composites ; Polymer crystallization and properties ; Nanopore and Nanochannel Transport Studies
Authors: Tuan Anh Nguyen | Quang Tung Nguyen
Source: Journal of Chemistry (article, 2020-08-08)
Field: Materials Science — Polymers and Plastics

Study on Synergies of Fly Ash with Multiwall Carbon Nanotubes in Manufacturing Fire Retardant Epoxy Nanocomposite In this study, fly ash (FA) and multiwalled carbon nanotubes (MWCNTs) were used to make environmentally friendly nanocomposites, which have high fire retardant properties and high mechanical properties. Industrial waste such as fly ash has become a major concern during the treatment of environmental pollution. MWCNTs were used in this experiment to enhance the flame retardant properties and mechanical properties of materials with fly ash additives. MWCNTs content (0.03, 0.04, and 0.05 wt.%) and fly ash content (30, 40, and 50 wt.%) were studied for three different levels. The flame retardancy of the material is significantly improved by the addition of fly ash/MWCNTs at different rates, especially at 0.04 wt. % MWCNTs and 40 wt. % fly ash with LOI at 26.8%. Regarding mechanical properties, tensile strength increases as fly ash/MWCNTs increase, up to a critical point. On the other hand, the compressive strength of composite increases continuously as fly ash/MWCNTs increase. Scanning electron microscopy (SEM) was used to observe the morphology of fly ash and MWCNTs as well as its distribution in the matrix. This will help analyze the influence of the effectiveness of the combination of fly ash and MWCNTs to the flame retardancy and mechanical properties of fly ash/MWCNTs/epoxy nanocomposites. Fly ash ; Fire retardant ; Nanocomposite ; Carbon nanotube ; Ultimate tensile strength ; Epoxy ; Composite material ; Environmental pollution ; Materials science ; Compressive strength ; Scanning electron microscope ; Chemistry ; Environmental science Flame retardant materials and properties ; Polymer Nanocomposites and Properties ; Carbon Nanotubes in Composites
Authors: Avishek Kumar | Ahmed Al-Jumaili | Kateryna Bazaka | Peter Mulvey | Jeffrey Warner | Mohan V. Jacob
Source: Materials (article, 2020-01-27)
Field: Materials Science — Materials Chemistry

In-Situ Surface Modification of Terpinen-4-ol Plasma Polymers for Increased Antibacterial Activity Surface modification of thin films is often performed to enhance their properties. In this work, in situ modification of Terpinen-4-ol (T4) plasma polymer is carried out via simultaneous surface functionalization and nanoparticle immobilization. Terpinen-4-ol plasma polymers surface were decorated with a layer of ZnO nanoparticles in an oxygen plasma environment immediately after polymer deposition. A combination of hydrophilic modification and ZnO nanoparticle functionalization of the T4 polymer surface led to an enhancement in antibacterial properties by factor of 3 (from 0.75 to 0.25 CFU.mm<sup>-2</sup>). In addition, ZnO nanoparticle-modified coatings demonstrated improved UV absorbing characteristics in the region of 300-400 nm by 60% relative to unmodified coatings. The ZnO modified coatings were transparent in the visible region of 400-700 nm. The finding points towards the potential use of ZnO nanoparticle-modified T4 plasma polymers as optically transparent UV absorbing coatings. In situ ; Surface modification ; Polymer ; Materials science ; Antibacterial activity ; Plasma ; Chemical engineering ; Composite material ; Chemistry ; Organic chemistry ; Bacteria ; Engineering ; Geology Nanoparticles: synthesis and applications ; Antimicrobial agents and applications ; Graphene and Nanomaterials Applications