jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Jianjun Liu | Kazushi Enomoto | Kotaro Takeda | Daishi Inoue | Yong‐Jin Pu
Source: Chemical Science (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Simple cubic self-assembly of PbS quantum dots by finely controlled ligand removal through gel permeation chromatography The geometry in self-assembled superlattices of colloidal quantum dots (QDs) strongly affects their optoelectronic properties and is thus of critical importance for applications in optoelectronic devices. Here, we achieve the selective control of the geometry of colloidal quasi-spherical PbS QDs in highly-ordered two and three dimensional superlattices: Disordered, simple cubic (sc), and face-centered cubic (fcc). Gel permeation chromatography (GPC), not based on size-exclusion effects, is developed to quantitatively and continuously control the ligand coverage of PbS QDs. The obtained QDs can retain their high stability and photoluminescence on account of the chemically soft removal of the ligands by GPC. With increasing ligand coverage, the geometry of the self-assembled superlattices by solution-casting of the GPC-processed PbS QDs changed from disordered, sc to fcc because of the finely controlled ligand coverage and anisotropy on QD surfaces. Importantly, the highly-ordered sc supercrystal usually displays unique superfluorescence and is expected to show high charge transporting properties, but it has not yet been achieved for colloidal quasi-spherical QDs. It is firstly accessible by fine-tuning the QD ligand density using the GPC method here. This selective formation of different geometric superlattices based on GPC promises applications of such colloidal quasi-spherical QDs in high-performance optoelectronic devices. Quantum dot ; Permeation ; Cubic crystal system ; Ligand (biochemistry) ; Gel permeation chromatography ; Superlattice ; Self-assembly ; Hexagonal crystal system ; Colloid ; Materials science ; Chemistry ; Chromatography ; Chemical engineering ; Crystallography ; Nanotechnology ; Physical chemistry ; Organic chemistry ; Optoelectronics ; Membrane ; Polymer ; Receptor Quantum Dots Synthesis And Properties ; Nanocluster Synthesis and Applications ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Valentin Evang | Johannes Reindl | Lisa Schäfer | Alexander Rochotzki | Pauline Pletzer‐Zelgert | Matthias Wuttig | Riccardo Mazzarello
Source: Advanced Materials (article, 2021-11-08)
Field: Materials Science — Materials Chemistry

Thermally Controlled Charge‐Carrier Transitions in Disordered PbSbTe Chalcogenides Binary and ternary chalcogenides have recently attracted much attention due to their wide range of applications including phase-change memory materials, topological insulators, photonic switches, and thermoelectrics. These applications require a precise control of the number and mobility of charge carriers. Here, an unexpected charge-carrier transition in ternary compounds from the PbTe-Sb<sub>2</sub> Te<sub>3</sub> pseudo-binary line is reported. Upon thermal annealing, sputtered thin films of PbSb<sub>2</sub> Te<sub>4</sub> and Pb<sub>2</sub> Sb<sub>2</sub> Te<sub>5</sub> undergo a transition in the temperature coefficient of resistance and in the type of the majority charge carriers from n-type to p-type. These transitions are observed upon increasing structural order within one crystallographic phase. To account for this striking observation, it is proposed that the Fermi energy shifts from the tail of the conduction band to the valence band because different levels of overall structural disorder lead to different predominant types of native point defects. This view is confirmed by an extensive computational study, revealing a transition from excess cations and Sb<sub>Pb</sub> for high levels of disorder to Pb<sub>Sb</sub> prevailing for low disorder. The findings will help fine-tune transport properties in certain chalcogenides via proper thermal treatment, with potential benefits for memories, thermoelectric material optimization, and neuromorphic devices. Materials science ; Charge carrier ; Ternary operation ; Condensed matter physics ; Thermoelectric effect ; Thermoelectric materials ; Electron mobility ; Annealing (glass) ; Charge ordering ; Phase transition ; Optoelectronics ; Chemical physics ; Charge (physics) ; Thermal conductivity ; Chemistry ; Thermodynamics ; Physics Phase-change materials and chalcogenides ; Advanced Thermoelectric Materials and Devices ; Chalcogenide Semiconductor Thin Films
Authors: Alfred Bazin | Luc Avérous | Éric Pollet
Source: Polymers (article, 2021-10-27)
Field: Materials Science — Biomaterials

Ferulic Acid as Building Block for the Lipase-Catalyzed Synthesis of Biobased Aromatic Polyesters Enzymatic synthesis of aromatic biobased polyesters is a recent and rapidly expanding research field. However, the direct lipase-catalyzed synthesis of polyesters from ferulic acid has not yet been reported. In this work, various ferulic-based monomers were considered for their capability to undergo CALB-catalyzed polymerization. After conversion into diesters of different lengths, the CALB-catalyzed polymerization of these monomers with 1,4-butanediol resulted in short oligomers with a DP<sub>n</sub> up to 5. Hydrogenation of the double bond resulted in monomers allowing obtaining polyesters of higher molar masses with DP<sub>n</sub> up to 58 and M<sub>w</sub> up to 33,100 g·mol<sup>-1</sup>. These polyesters presented good thermal resistance up to 350 °C and T<sub>g</sub> up to 7 °C. Reduction of the ferulic-based diesters into diols allowed preserving the double bond and synthesizing polyesters with a DP<sub>n</sub> up to 19 and M<sub>w</sub> up to 15,500 g·mol<sup>-1</sup> and higher T<sub>g</sub> (up to 21 °C). Thus, this study has shown that the monomer hydrogenation strategy proved to be the most promising route to achieve ferulic-based polyester chains of high DP<sub>n</sub>. This study also demonstrates for the first time that ferulic-based diols allow the synthesis of high T<sub>g</sub> polyesters. Therefore, this is an important first step toward the synthesis of competitive biobased aromatic polyesters by enzymatic catalysis. Lipase ; Polyester ; Ferulic acid ; Catalysis ; Organic chemistry ; Chemistry ; Block (permutation group theory) ; Enzyme ; Biochemistry ; Mathematics biodegradable polymer synthesis and properties ; Enzyme Catalysis and Immobilization ; Biochemical and biochemical processes
Authors: Christine K. Luscombe | Uday Maitra | Michael G. Walter | Susanne Κ. Wiedmer
Source: Chemistry Teacher International (article, 2021-03-01)
Field: Materials Science — Polymers and Plastics

Theoretical background on semiconducting polymers and their applications to OSCs and OLEDs Abstract Organic electronics has developed rapidly over the past 40 years. In 1977, a seminal discovery was reported that showed that a polymer known as polyacetylene could conduct electricity as well as metals could. This was a groundbreaking discovery that led to a Nobel Prize in Chemistry in 2000. The polymers that are used in organic electronics have now been widely studied for use in organic solar cells (OSCs), organic field effect transistors (OFETs), printable electronics, flexible electronics, antistatic coatings, actuators, and more recently in bioelectronics. In particular, the utility of organic electronics is seen in the commercial success of using organic electronic materials in organic light-emitting diodes (OLEDs) where OLED displays can be seen in mobile phones and as flat panel displays. In this paper, we provide a tutorial targeting upper secondary students describing how these special classes of polymers function, and how they can be synthesized. The paper further discusses the use of these materials in two applications: organic solar cells and organic light-emitting diodes. The paper ends with a brief discussion about hands-on activities that can be carried out in the upper secondary student science classroom. OLED ; Organic electronics ; Bioelectronics ; Organic solar cell ; Polyacetylene ; Electronics ; Nanotechnology ; Materials science ; Conductive polymer ; Polymer ; Transistor ; Optoelectronics ; Electrical engineering ; Engineering ; Composite material Conducting polymers and applications ; Organic Electronics and Photovoltaics ; Advanced Sensor and Energy Harvesting Materials
Authors: José Alemán | Rubén Mas‐Ballesté
Source: Frontiers in Chemistry (review, 2021-06-24)
Field: Materials Science — Materials Chemistry

Photocatalytic Oxidation Reactions Mediated by Covalent Organic Frameworks and Related Extended Organic Materials Covalent Organic Frameworks (COFs) and related extended organic materials have been widely used as photocatalysts in the last few years. Such interest arises from the wide range of covalent linkages employed in their construction, which offer many possibilities to design extended frameworks and to link photoactive building blocks. Thus, the potential utility of predesigned organic photoactive fragments can be synergistically added to the inherent advantages of heterogeneous catalysis, such as recyclability and easy separation of catalyst. In this overview, the current state of the art on the design of organic materials for photocatalytic oxidation reactions will be presented. The designing process of these materials is usually conditioned by the generally accepted concept that crystallinity and porosity defines the quality of the heterogeneous catalysts obtained. The care for the structural integrity of materials obtained is understandable because many properties and applications are intimately related to these features. However, the catalytic activity does not always directly depends on these characteristics. A critical compilation of the available literature is performed in order to offer a general perspective of the use of COFs and Covalent Triazine Frameworks (CTFs) in photocatalytic oxidation processes, including water oxidation, which constitute an important outcome relevant to artificial photosynthesis. Photocatalysis ; Catalysis ; Covalent bond ; Triazine ; Nanotechnology ; Materials science ; Crystallinity ; Covalent organic framework ; Rational design ; Chemistry ; Organic chemistry Covalent Organic Framework Applications ; Advanced Photocatalysis Techniques ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Alice Sciortino | Francesco Ferrante | Gil Gonçalves | Gerard Tobías | Radian Popescu | Dagmar Gerthsen | Nicolò Mauro | Gaetano Giammona | Gianpiero Buscarino | F. M. Gelardi | S. Agnello | M. Cannas | Dario Duca | Fabrizio Messina
Source: ACS Applied Materials & Interfaces (article, 2021-10-05)
Field: Materials Science — Materials Chemistry

Ultrafast Interface Charge Separation in Carbon Nanodot–Nanotube Hybrids Carbon dots are an emerging family of zero-dimensional nanocarbons behaving as tunable light harvesters and photoactivated charge donors. Coupling them to carbon nanotubes, which are well-known electron acceptors with excellent charge transport capabilities, is very promising for several applications. Here, we first devised a route to achieve the stable electrostatic binding of carbon dots to multi- or single-walled carbon nanotubes, as confirmed by several experimental observations. The photoluminescence of carbon dots is strongly quenched when they contact either semiconductive or conductive nanotubes, indicating a strong electronic coupling to both. Theoretical simulations predict a favorable energy level alignment within these complexes, suggesting a photoinduced electron transfer from dots to nanotubes, which is a process of high functional interest. Femtosecond transient absorption confirms indeed an ultrafast (<100 fs) electron transfer independent of nanotubes being conductive or semiconductive in nature, followed by a much slower back electron transfer (≈60 ps) from the nanotube to the carbon dots. The high degree of charge separation and delocalization achieved in these nanohybrids entails significant photocatalytic properties, as we demonstrate by the reduction of silver ions in solution. The results are very promising in view of using these "all-carbon" nanohybrids as efficient light harvesters for applications in artificial photocatalysis and photosynthesis. Materials science ; Carbon nanotube ; Electron transfer ; Nanotechnology ; Photoluminescence ; Photoinduced charge separation ; Delocalized electron ; Carbon nanobud ; Nanodot ; Photocatalysis ; Nanotube ; Optical properties of carbon nanotubes ; Optoelectronics ; Artificial photosynthesis ; Photochemistry Carbon and Quantum Dots Applications ; Graphene research and applications ; Quantum Dots Synthesis And Properties
Authors: Tomasz Jeliński | Dawid Stasiak | Tomasz Kosmalski | Piotr Cysewski
Source: Pharmaceutics (article, 2021-07-22)
Field: Chemistry — Spectroscopy

Experimental and Theoretical Study on Theobromine Solubility Enhancement in Binary Aqueous Solutions and Ternary Designed Solvents The solubility of theobromine was studied both experimentally and theoretically. The solubility was determined spectrophotometrically at 25 °C in neat organic solvents, aqueous binary mixtures, Natural Deep Eutectic Solvents (NADES) and ternary NADES mixtures with water. It was found that addition of water in unimolar proportions with some organic solvents increases theobromine solubility compared to neat solvents. Additionally, using NADES results in a solubility increase of the studied compound not only in relation to water but also DMSO. The addition of water (0.2 molar fraction) to NADES is responsible for an even larger increase of solubility. The measured solubilities were interpreted in terms of three theoretical frameworks. The first one-belonging to the set of data reduction techniques-proved to be very efficient in quantitative back-computations of excess solubility of theobromine in all studied systems. The default approach utilizing the well-recognized COSMO-RS (Conductor-like Screening Model for Real Solvents) framework offered at most a qualitative solubility description. The extended search for possible contacts provided evidence for the existence of many intermolecular complexes that alter the electron density of the solute molecule, thus influencing solubility computations. Taking into account such intermolecular contacts by using the COSMO-RS-DARE (Conductor-like Screening Model for Realistic Solvation-Dimerization, Aggregation, and Reaction Extension) framework seriously increased the accuracy of solubility computations. Solubility ; Chemistry ; Ternary operation ; Intermolecular force ; Molar solubility ; Theobromine ; Dissolution ; Eutectic system ; Solvation ; Aqueous solution ; Thermodynamics ; Computational chemistry ; Organic chemistry ; COSMO-RS ; Molecule ; Ionic liquid Analytical Chemistry and Chromatography ; Crystallization and Solubility Studies ; Ionic liquids properties and applications
Authors: Bianca N. Lourenço | Rúben F. Pereira | Cristina C. Barrias | Claudia Fischbach | Carla Oliveíra | Pedro L. Granja
Source: Nanomaterials (article, 2021-01-23)
Field: Materials Science — Biomaterials

Engineering Modular Half-Antibody Conjugated Nanoparticles for Targeting CD44v6-Expressing Cancer Cells Gastric cancer (GC) remains a major cause of death worldwide mainly because of the late detection in advanced stage. Recently, we proposed CD44v6 as a relevant marker for early detection of GC, opening new avenues for GC-targeted theranostics. Here, we designed a modular nanoscale system that selectively targets CD44v6-expressing GC cells by the site-oriented conjugation of a new-engineered CD44v6 half-antibody fragment to maleimide-modified polystyrene nanoparticles (PNPs) via an efficient bioorthogonal thiol-Michael addition click chemistry. PNPs with optimal particle size (200 nm) for crossing a developed biomimetic CD44v6-associated GC stromal model were further modified with a heterobifunctional maleimide crosslinker and click conjugated to the novel CD44v6 half-antibody fragment, obtained by chemical reduction of full antibody, without affecting its bioactivity. Collectively, our results confirmed the specific targeting ability of CD44v6-PNPs to CD44v6-expressing cells (1.65-fold higher than controls), highlighting the potential of CD44v6 half-antibody conjugated nanoparticles as promising and clinically relevant tools for the early diagnosis and therapy of GC. Additionally, the rational design of our nanoscale system may be explored for the development of several other nanotechnology-based disease-targeted approaches. Antibody ; Conjugated system ; Chemistry ; Bioorthogonal chemistry ; Maleimide ; Click chemistry ; Nanotechnology ; Molecular biology ; Cancer research ; Materials science ; Combinatorial chemistry ; Medicine ; Biology ; Immunology Nanoparticle-Based Drug Delivery ; Glycosylation and Glycoproteins Research ; Immunotherapy and Immune Responses
Authors: Shi‐Qiang Wang | Shaza Darwish | Debobroto Sensharma | Michael J. Zaworotko
Source: Materials Advances (article, 2021-12-10)
Field: Chemistry — Inorganic Chemistry

Tuning the switching pressure in square lattice coordination networks by metal cation substitution Coordination networks that undergo guest-induced switching between nonporous and porous phases are of increasing interest as the resulting stepped sorption isotherms can offer exceptional working capacities for gas storage applications. Substitution (logic) ; Metal ; Square lattice ; Lattice (music) ; Square (algebra) ; Materials science ; Crystallography ; Chemistry ; Condensed matter physics ; Metallurgy ; Mathematics ; Physics ; Computer science ; Geometry Metal-Organic Frameworks: Synthesis and Applications ; Covalent Organic Framework Applications ; Organic and Molecular Conductors Research
Authors: Eliézer Jäger | Jana Humajová | Yusuf Dölen | Jan Kučka | Alessandro Jäger | Rafał Konefał | Jan Pankrác | Ewa Pavlová | Tomáš Heizer | Luděk Šefc | Martin Hrubý | Carl G. Figdor | Martijn Verdoes
Source: Advanced Healthcare Materials (article, 2021-05-29)
Field: Materials Science — Biomaterials

Enhanced Antitumor Efficacy through an “AND gate” Reactive Oxygen‐Species‐Dependent pH‐Responsive Nanomedicine Approach Anticancer drug delivery strategies are designed to take advantage of the differential chemical environment in solid tumors independently, or to high levels of reactive oxygen species (ROS) or to low pH, compared to healthy tissue. Here, the design and thorough characterization of two functionalizable "AND gate" multiresponsive (MR) block amphiphilic copolymers are reported, aimed to take full advantage of the coexistence of two chemical cues-ROS and low pH-present in the tumor microenvironment. The hydrophobic blocks contain masked pH-responsive side chains, which are exposed exclusively in response to ROS. Hence, the hydrophobic polymer side chains will undergo a charge shift in a very relevant pH window present in the extracellular milieu in most solid tumors (pH 5.6-7.2) after demasking by ROS. Doxorubicin (DOX)-loaded nanosized "AND gate" MR polymersomes (MRPs) are fabricated via microfluidic self-assembly. Chemical characterization reveals ROS-dependent pH sensitivity and accelerated DOX release under influence of both ROS and low pH. Treatment of tumor-bearing mice with DOX-loaded nonresponsive and "AND gate" MRPs dramatically decreases cardiac toxicity. The most optimal "AND gate" MRPs outperform free DOX in terms of tumor growth inhibition and survival, shedding light on chemical requirements for successful cancer nanomedicine. Reactive oxygen species ; Nanomedicine ; Chemistry ; Oxygen ; Pharmacology ; Medicine ; Cancer research ; Nanotechnology ; Biochemistry ; Nanoparticle ; Materials science ; Organic chemistry Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics ; Graphene and Nanomaterials Applications
Authors: Louise van Tonder | Frederick J. W. J. Labuschagné
Source: Polymers (review, 2021-10-28)
Field: Materials Science — Materials Chemistry

Systematic Literature Review of the Effect of Layered Double Hydroxides on the Mechanical Properties of Rubber Layered double hydroxides (LDHs) have attracted interest as reinforcing fillers in elastomers due to their ease of synthesis and customisability. A systematic review was performed on the effect of LDHs on the mechanical properties of elastomers using the Scopus database. Of the 61 articles relevant to the search criteria, the majority were published on polyurethane (PU) and nitrile butadiene rubber (NBR). Mg-Al LDH was used in most of the studies and Zn-Al LDH was used second most common. LDH can act as a reinforcing filler, typically increasing tensile strength even at low concentrations, so it could be used as an alternative to traditional reinforcing fillers for elastomers. LDH can also be made a functional filler by selecting the right metals and interlayer anions. It was found that Mg-Al LDH and Zn-Al LDH can both participate in crosslinking reactions and can replace MgO and ZnO, respectively. Less Zn ions are required for crosslinking when LDH is used than when ZnO is used, making LDH more environmentally friendly. Organic modification is usually required to improve compatibility with the elastomer matrix, especially in non-polar elastomers. It enables exfoliation of the LDH and intercalation of polymer chains into the LDH interlayer to occur. Organic modifiers can also be used to functionalise the LDH. Stearic acid used in crosslinking systems can be replaced by stearate anions from stearate-modified LDH. Elastomer ; Layered double hydroxides ; Materials science ; Natural rubber ; Ultimate tensile strength ; Stearate ; Composite material ; Polymer ; Stearic acid ; Nitrile rubber ; Intercalation (chemistry) ; Filler (materials) ; Tear resistance ; Chemical engineering ; Chemistry ; Organic chemistry ; Hydroxide Layered Double Hydroxides Synthesis and Applications ; Magnesium Oxide Properties and Applications ; Polymer Nanocomposites and Properties
Authors: Mattia Negroni | Dennis Kurzbach
Source: Communications Chemistry (article, 2021-10-22)
Field: Chemistry — Spectroscopy

Residue-resolved monitoring of protein hyperpolarization at sub-second time resolution Abstract Signal-enhancement techniques for NMR spectroscopy are important to amplify the weak resonances provided by nuclear spins. Recently, ‘hyperpolarization’ techniques have been intensively investigated. These provide nuclear spin states far from equilibrium yielding strong signal boosts up to four orders of magnitude. Here we propose a method for real-time NMR of ‘hyperpolarized’ proteins at residue resolution. The approach is based on dissolution dynamic nuclear polarization ( d -DNP), which enables the use of hyperpolarized buffers that selectively boost NMR signals of solvent-exposed protein residues. The resulting spectral sparseness and signal enhancements enable recording of residue-resolved spectra at a 2 Hz sampling rate. Thus, we monitor the hyperpolarization level of different protein residues simultaneously under near-physiological conditions. We aim to address two points: 1) NMR experiments are often performed under conditions that increase sensitivity but are physiologically irrelevant; 2) long signal accumulation impedes fast real-time monitoring. Both limitations are of fundamental relevance to ascertain pharmacological relevance and study protein kinetics. Hyperpolarization (physics) ; Spins ; Chemistry ; Nuclear magnetic resonance spectroscopy ; Nuclear magnetic resonance ; NMR spectra database ; Two-dimensional nuclear magnetic resonance spectroscopy ; Analytical Chemistry (journal) ; Spectral line ; Physics ; Chromatography ; Stereochemistry Advanced NMR Techniques and Applications ; Solid-state spectroscopy and crystallography ; Electron Spin Resonance Studies