jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Martina Di Francesco | Rosita Primavera | Davide Romanelli | Roberto Palomba | Tiziano Catelani | Christian Celia | Luisa Di Marzio | Massimo Fresta | Daniele Di Mascolo | Paolo Decuzzi
Source: arXiv (Cornell University) (preprint, 2019-03-08)
Field: Materials Science — Biomaterials

Hierarchical microplates as drug depots with controlled geometry, rigidity and therapeutic efficacy A variety of microparticles have been proposed for the sustained and localized delivery of drugs whit the objective of increasing therapeutic indexes by circumventing filtering organs and biological barriers. Yet, the geometrical, mechanical and therapeutic properties of such microparticles cannot be simultaneously and independently tailored during the fabrication process in order to optimize their performance. In this work, a top-down approach is employed to realize micron-sized polymeric particles, called microPlates (uPLs), for the sustained release of therapeutic agents. uPLs are square hydrogel particles, with an edge length of 20 um and a height of 5 um, made out of poly (lactic co glycolic acid) (PLGA). During the synthesis process, the uPL Young's modulus can be varied from 0.6 to 5 MPa by changing PLGA amounts from 1 to 7.5 mg, without affecting the uPL geometry. Within the porous uPL matrix, different classes of therapeutic payloads can be incorporated including molecular agents, such as the anti-inflammatory dexamethasone (DEX), and nanoparticles, containing themselves imaging and therapeutic molecules. As a proof of principle, uPLs are loaded with free DEX and 200 nm spherical polymeric nanoparticles, carrying DEX molecules (DEX-SPNs). Electron and fluorescent confocal microscopy analyses document the uniform distribution and stability of molecular and nano agents within the uPL matrix. This multiscale, hierarchical microparticle releases DEX for at least 10 days. The inclusion of DEX-SPNs serves to minimize the initial burst release and modulate the diffusion of DEX molecules out of the uPL matrix. The pharmacological and therapeutic properties together with the fine tuning of geometry and mechanical stiffness make uPLs a unique polymeric depot for the potential treatment of cancer, cardiovascular and chronic, inflammatory diseases. Nanoparticle ; Drug delivery ; Materials science ; PLGA ; Biomedical engineering ; Nanotechnology ; Molecule ; Biophysics ; Chemical engineering ; Chemistry ; Medicine ; Organic chemistry Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; Advancements in Transdermal Drug Delivery
Authors: Timothée Stassin | Steve Waitschat | Niclas Heidenreich | Helge Reinsch | Finn Puschkell | Dmitry V. Kravchenko | Ivo Stassen | Jonas van Dinter | Rhea Verbeke | Marcel Dickmann | Werner Egger | Ivo F.J. Vankelecom | Dirk De Vos | Rob Ameloot | Norbert Stock
Source: ChemRxiv (preprint, 2019-06-24)
Field: Chemistry — Inorganic Chemistry

Aqueous Flow Reactor and Vapour-Assisted Synthesis of Aluminium Dicarboxylate Metal-Organic Frameworks for Use as Water Adsorbents Energy-efficient indoors temperature control can be realised through adsorption chillers or adsorption heat pumps based on the reversible adsorption and desorption of water in porous materials. Stable microporous aluminium-based metal-organic frameworks (MOFs) present promising water sorption properties for this goal. The development of synthesis routes that make use of available and affordable building blocks and avoid the use of organic solvents is crucial to advance this field. In this work, two scalable synthesis routes under mild reaction conditions were developed for aluminium-based MOFs: (1) in aqueous solutions using a continuous flow reactor and (2) through the vapour-assisted conversion of solid precursors. Fumaric acid, its methylated analogue mesaconic acid, as well as mixtures of the two were used as linkers. The synthesis conditions determine the crystal structure (symmetry and topology), either the MIL-53 or MIL-68 type with square-grid or kagome-grid topology, respectively. Fine-tuning resulted in new MOF materials thus far inaccessible through conventional synthesis routes. Furthermore, by varying the linker ratio, the water sorption properties can be continuously adjusted while retaining the sigmoidal isotherm shape advantageous for heat transformation applications. Adsorption ; Microporous material ; Materials science ; Sorption ; Aqueous solution ; Metal-organic framework ; Chemical engineering ; Aluminium ; Topology (electrical circuits) ; Chemistry ; Organic chemistry ; Composite material Metal-Organic Frameworks: Synthesis and Applications ; Adsorption and Cooling Systems ; Covalent Organic Framework Applications
Authors: S. Mahn | E. Kemnitz
Source: HZB Repository (Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB)) (article, 2019-01-01)
Field: Materials Science — Biomaterials

Modification of low?molecular polylactic acid by CaF2 nanoparticles A new approach to change its material properties Due to environmental problems and the increasing waste of resources, sustainable biodegradable plastics has become a great topic worldwide. In this communique, we present a simple low cost synthesis to improve one of these typically used materials, PLA polylactic acid . CaF2 nanoparticles synthesized according the fluorolytic sol gel synthesis in lactic acid give access to fine tune the material characteristics of LMPLA low molecular polylactic acid due to a simply to apply polycondensation reaction of lactic acid monomers. Thus, for the first time, homo dispersed CaF2 up to 15 amp; 8201;wt in PLA is synthesized as cubic nanomaterial improving the characteristics of a subsequently formed thermoplastic in comparison with a polycondensed PLA reference material. A detailed characterization of the synthesized material is provided by using X ray imaging, TEM, 19F MAS NMR, sol XRD, MALDI TOF, and nanoindentation. The results reveal a promising first step of a modification opportunity of LMPLA regarding melting point, elastic modulus, and hardness. This way it is possible to adjust material characteristics in a simple and inexpensive way, which might broaden the field of possible applications and make biodegradable plastics a more competitive alternative to conventional used ones Polylactic acid ; Lactic acid ; Thermoplastic ; Nanomaterials ; Nanoparticle ; Condensation polymer ; Biodegradable polymer biodegradable polymer synthesis and properties ; Microplastics and Plastic Pollution ; Carbon dioxide utilization in catalysis
Authors: Palraj Kasinathan | Charlotte Lang | Sambhu Radhakrishnan | Josefine Schnee | Cécile D’Haese | Eric Breynaert | Johan A. Martens | Éric M. Gaigneaux | Alain M. Jonas | Antony E. Fernandes
Source: Chemistry - A European Journal (article, 2019-04-08)
Field: Chemistry — Organic Chemistry

Cover Feature: “Click” Silica‐Supported Sulfonic Acid Catalysts with Variable Acid Strength and Surface Polarity (Chem. Eur. J. 27/2019) How do you like your acid catalyst? A robust and modular method is presented for the preparation of silica-supported sulfonic acid catalysts. The strategy makes it possible to fine tune both their acid strength and surface polarity, taking advantage of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) and further modification of the formed triazole link. The artwork displays an assembly line that reacts the azide-functionalized mesoporous silica particles with different alkynes and electrophiles to provide a family of bespoke solid acid catalysts. More information can be found in the Full Paper by A. E. Fernandes et al. on page 6753. Catalysis ; Sulfonic acid ; Cycloaddition ; Click chemistry ; Azide ; Chemistry ; Mesoporous silica ; Surface modification ; Combinatorial chemistry ; Polymer chemistry ; Mesoporous material ; Organic chemistry Click Chemistry and Applications ; Nanomaterials for catalytic reactions
Authors: Martin Salinga
Source:  (article, 2019-05-01)
Field: Materials Science — Materials Chemistry

Single-Element Phase Change Memory Phase Change Memory (PCM) is a mature technology that is commercially available for several years now, e.g. in form of the 3D-Xpoint by Intel and Micron. Further spatial scaling towards higher device density promises better performance. At the same time, it further aggravates fundamental issues that have regularly been reported over the past years. The functional principle of PCM involves not only the application of high electric fields but also heating of the active material above its melting point. Under these harsh operating conditions, the different chemical elements are found to segregate and alter away from the fine-tuned original composition with its specific set of electrical switching properties. Such segregation problems can be resolved if the phase change material is radically simplified from a commonly quaternary alloy into a pure chemical element. This presentation discusses various aspects that ought to be considered in such an endeavor. Phase-change memory ; Element (criminal law) ; Scaling ; Shape-memory alloy ; Phase-change material ; Computer science ; Phase (matter) ; Non-volatile memory ; Melting point ; Set (abstract data type) ; Presentation (obstetrics) ; Materials science ; Mechanical engineering ; Phase change ; Engineering physics ; Engineering ; Physics ; Computer hardware ; Artificial intelligence ; Composite material ; Geometry Phase-change materials and chalcogenides ; Advanced Memory and Neural Computing ; Chalcogenide Semiconductor Thin Films
Authors: Alexander Sinitskii
Source: ECS Meeting Abstracts (article, 2019-05-01)
Field: Materials Science — Materials Chemistry

(Invited) Atomically Precise Graphene Nanoribbons: From Synthesis to Applications Atomically precise graphene nanoribbons (GNRs) are at the forefront of nanocarbon research and hold great promise for electronic and optoelectronic applications. Theoretical studies have shown that narrow GNRs possess interesting electronic and magnetic properties that strongly depend on the nanoribbon’s width and edge structure. GNRs with different structures can be synthesized with atomic precision and fine-tuned properties by coupling properly designed molecular precursors and planarization of the resulting polymers. In this talk, I will discuss our efforts on designing and synthesizing new atomically precise GNRs for electronic applications. First, I will describe a scalable bottom-up solution approach for atomically precise GNRs that is based on Yamamoto coupling of pre-synthesized molecular precursors followed by cyclodehydrogenation using Scholl reaction. This approch can be applied to the synthesis of a variety of GNRs, including pristine and nitrogen-doped GNRs with the chevron structure. Then, I will demonstrate that the electrical conductivity of atomically precise chevron GNRs can be improved by their lateral extension. Two types of new laterally extended chevron GNRs (eGNRs) were synthesized in solution, and their high structural quality was confirmed by a number of characterization techniques, including high-resolution scanning tunneling microscopy and Raman spectroscopy combined with a computational analysis. Optical spectroscopy and scanning tunneling spectroscopy showed that lateral extension of chevron GNRs resulted in the decrease of their electronic bandgap. We developed a procedure for processing eGNRs into uniform thin films that exhibit improved electrical conductivity compared to similar films of regular chevron GNRs. The eGNR films were employed in gas sensors that showed very high responsivity to low molecular weight alcohols compared to similar sensors based on benchmark graphitic materials, such as graphene and graphene oxide. Finally, we demonstrated the first electronic nose system based on atomically precise GNRs that could reliably recognize analytes of nearly the same chemical nature, such as methanol and ethanol. Overall, this talk will demonstrate the entire path from designing new atomically precise GNRs with improved properties to their bottom-up synthesis, characterization, processing and implementation in electronic devices. Chevron (anatomy) ; Graphene nanoribbons ; Materials science ; Raman spectroscopy ; Nanotechnology ; Graphene ; Scanning tunneling microscope ; Spectroscopy ; Optoelectronics ; Optics ; Physics Graphene research and applications ; Fullerene Chemistry and Applications ; Graphene and Nanomaterials Applications
Authors: Raquel C. R. Gonçalves | Susana P. G. Costa | M. Manuela M. Raposo
Source: RepositóriUM (Universidade do Minho) (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Synthesis and characterization of a fluorescent BODIPY derivative Despite existing for almost a century, fluorescent dyes continue to attract the attention of scientists from an ever expanding multidisciplinary areas. Among the many diverse fluorescent molecules, 3-difluoroborodipyrromethene (BODIPY) derivatives, have become a cornerstone for innovative applications such as biological fluorescent labelling, electroluminescent devices, dye sensitized solar cells (DSSCs), photodynamic therapy (PDT), optical sensors etc. Recently, BODIPYs have received great attention because of their advantageous features: photochemical stability, sharp absorption with high intensity in visible to NIR region and high fluorescence quantum yields. In fact, BODIPY came to be known to the biochemists and biologists as a photostable substitute for fluorescein. Furthermore, the BODIPY core can be chemically modified in order to fine tune the optical properties or add new functionalities, such as receptor groups selective to analytes in the case of sensors. In continuation of the investigation developed in our research group, we report in this work the synthesis and the characterization of a BODIPY derivative using several spectroscopic/spectrophotometric techniques. Evaluation of their optical properties showed its potential application as a novel fluorescent probe for in vivo/in vitro studies. BODIPY ; Fluorescence ; Derivative (finance) ; Characterization (materials science) ; Chemistry ; Computer science ; Materials science ; Nanotechnology ; Physics ; Business ; Optics Luminescence and Fluorescent Materials
Authors: Erika Kutálková | Miroslav Mrlík | Markéta Ilčíková | Josef Osička | Michal Sedlačík | Jaroslav Mosnáček
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2019-02-24)
Field: Materials Science — Polymers and Plastics

Enhanced and Tunable Electrorheological Capability using Surface Initiated Atom Transfer Radical Polymerization Modification with Simultaneous Reduction of the Graphene Oxide by Silyl-Based Polymer Grafting In this study, a verified process of the “grafting from” approach using surface initiated atom<br> transfer radical polymerization was applied for the modification of a graphene oxide (GO) surface.<br> This approach provides simultaneous grafting of poly(2-(trimethylsilyloxy)ethyl methacrylate)<br> (PHEMATMS) chains and a controllable reduction of the GO surface. This allows the fine tuning of its<br> electrical conductivity, which is a crucial parameter for applications of such hybrid composite particles<br> in electrorheological (ER) suspensions. The successful coating was confirmed by transmission<br> electron microscopy and Fourier-transform infrared spectroscopy. The molecular characteristics of<br> PHEMATMS were characterized by gel permeation chromatography. ER performance was elucidated<br> using a rotational rheometer under various electric field strengths and a dielectric spectroscopy<br> to demonstrate the direct impact of both the relaxation time and dielectric relaxation strength on<br> the ER effectivity. Enhanced compatibility between the silicone oil and polymer-modified GO<br> particles was investigated using contact angle measurements and visual sedimentation stability<br> determination. It was clearly proven that the modification of the GO surface improved the ER<br> capability of the system due to the tunable conductivity during the surface-initiated atom transfer<br> radical polymerization (SI-ATRP) process and the enhanced compatibility of the GO particles,<br> modified by polymer containing silyl structures, with silicone oil. These unique ER properties<br> of this system appear very promising for future applications in the design of ER suspensions. Atom-transfer radical-polymerization ; Grafting ; Graphene ; Surface modification ; Silylation ; Materials science ; Oxide ; Polymer ; Polymerization ; Polymer chemistry ; Chemical engineering ; Nanotechnology ; Chemistry ; Composite material ; Catalysis ; Organic chemistry Polymer composites and self-healing ; Synthetic Organic Chemistry Methods
Authors: Nicholas P. Lyons | Abhinav Nishant | Laura E. Anderson | Tristan S. Kleine | Katrina M. Konopka | Jeffrey Pyun | Robert A. Norwood
Source:  (article, 2019-03-05)
Field: Materials Science — Polymers and Plastics

Polymeric infrared antireflection coating for silicon substrates (Conference Presentation) Antireflective coatings (ARC) are a necessary element of solar cells and infrared (IR) optical applications. Current state-of-the-art coatings consist of materials such as TiO2 and Si3N4 deposited on silicon via chemical vapor deposition (CVD). This method of coating is undesirable due to the costly, tedious, and time intensive nature of the process. Herein, we have developed a novel antireflective coating (ARC) that is facile in nature. Through the implementation of high sulfur content polymers, with ultrahigh refractive index, and near to mid infrared (IR) transparency, we have been able to demonstrate high-quality films via spin/dip coating. This polymer was produced via inverse vulcanization of elemental sulfur, a byproduct of petroleum refining, and the organic monomer 1,3-diisopropenylbenzene (DIB) to yield poly(sulfur-r-(1,3-diisopropenylbenzene)) (poly(s-r-DIB)). The reaction product (poly(s-r-DIB)) was taken up into solution and deposited directly onto a silicon substrate. To verify the performance of a quarter wave antireflection coating, the spectra of the coated silicon wafer was taken. In this we found we could create a high performance, single layer, antireflection coating. Due to the unique nature of the polymer (poly(s-r-DIB)) used in this system we were able to fine tune the thickness of the coating, and therefore the target wavelength in which desired performance could be observed. Further investigation of the system is underway, as the polymer's index can be tuned to fit a variety of substrates, making this system ideal for a multitude of antireflective applications. Anti-reflective coating ; Materials science ; Coating ; Silicon ; Wafer ; Polymer ; Optical coating ; Chemical vapor deposition ; Optoelectronics ; Chemical engineering ; Nanotechnology ; Composite material Synthesis and properties of polymers ; Advanced Fiber Optic Sensors ; Silicone and Siloxane Chemistry
Authors: Kefeng Ping | Alan Braschinsky | Mahboob Alam | Rohit Bhadoria | Valdek Mikli | Arvo Mere | Jaan Aruväli | Sergei Vlassov | Mati Kook | Mihkel Rähn | Väino Sammelselg | Kaido Tammeveski | Nadežda Kongi | Pavel Starkov
Source: ChemRxiv (preprint, 2019-02-07)
Field: Chemistry — Inorganic Chemistry

Fused Hybrid Linkers for Metal–Organic Frameworks-Derived Bifunctional Oxygen Electrocatalysts Preparation of electrocatalysts often relies on the use of multiple starting materials – inorganic salts or organometallic precursors, nanostructured carbon supports, organic additives, dopants and carbonization under modifying atmospheres (e.g. NH3 or H2) – with the examples of electrocatalysts arising from a single precursor being much less common. Herein, we have surveyed a series of heterobivalent scaffolds to identify an iron/benzimidazole-based metal– organic framework as a uniform starting material. By merging the catechol and imidazole units together, we get direct entry into a highly efficient bifunctional oxygen electrocatalyst, which alleviates the need for additional dopants and modifying conditions (ORR: Eon = 1.01 V, E1/2 = 0.87 V vs. RHE in 0.1 M KOH; OER: 1.60 V @10 mA cm–2 in 0.1 M KOH; ∆E = 0.73 V). We demonstrate that by fine-tuning the chemical nature of an organic linker, one is able modulate the electrochemical properties of a single precursor-derived electrocatalyst material. Bifunctional ; Electrocatalyst ; Carbonization ; Dopant ; Electrochemistry ; Materials science ; Metal-organic framework ; Oxygen evolution ; Metal ; Inorganic chemistry ; Chemistry ; Combinatorial chemistry ; Nanotechnology ; Chemical engineering ; Catalysis ; Organic chemistry ; Electrode ; Doping Metal-Organic Frameworks: Synthesis and Applications ; Electrocatalysts for Energy Conversion ; Polyoxometalates: Synthesis and Applications
Authors: Qianqian Zhang
Source: Carolina Digital Repository (University of North Carolina at Chapel Hill) (article, 2019-08-16)
Field: Materials Science — Polymers and Plastics

Design and Synthesis of Conjugated Polymers for Organic Photovoltaics: Tuning the Conjugated Backbone and the Substituents Developing new conjugated polymer materials has been one of the most important driving forces for improving the performance of organic photovoltaics. This dissertation has been focused on structural design of polymers, including fine-tuning the backbone and the substituents of the polymers in order to adjust specific properties and improve the efficiency of organic photovoltaics. This dissertation details new methodologies to prepare the designed polymers and explores the structure-property relationship. We first developed regio-regular and regio-random terpolymers based on two parent copolymers with complementary absorption range. We found that adequate aggregation of these terpolymers is necessary for high performance photovoltaics. We then incorporated fluorine substituents into π linker thiophene units between the donor and the acceptor units and succeeded in controlling the positions and amount of fluorine substituents on the polymer backbone. The efficiency of the photovoltaics was remarkably improved by the fluorinated thiophene units. More importantly, we demonstrated the beneficial effects of fluorinated thiophene on improving the hole mobility and the importance of high hole mobility in improving fill factors of photovoltaics using eight structurally related polymers. Finally, in order to lower the bandgap of the polymers, we introduced strong electron withdrawing cyano group to the acceptor units. We systematically study the effect of cyano substitution on the properties of the polymers and the polymer solar cells by controlling the amount of cyano substituents. With single cyano substitution, a high device efficiency of ~ 8.6% was achieved for the monoCNTAZ polymer. All the works highlight the importance of optimizing the polymer structure to reach high solar cell performance. Conjugated system ; Organic solar cell ; Polymer ; Photovoltaics ; Materials science ; Chemistry ; Nanotechnology ; Photovoltaic system ; Organic chemistry ; Engineering ; Electrical engineering Conducting polymers and applications ; Organic Electronics and Photovoltaics