jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Nandini Sarkar | Sean Parkin | Aron J. Huckaba
Source: Crystal Growth & Design (article, 2021-06-30)
Field: Chemistry — Physical and Theoretical Chemistry

Structural Study of Hydrogen-Bond Driven Cocrystallization of Pyridyl-Bithiophene Based Compounds Thiophene-based compounds have been extensively studied due to their electronic and optical properties, which find application in organic semiconductors. There are multiple reports describing the fine-tuning of these and other specific material properties. In this study, we conduct a systematic cocrystallization screen of two thiophene-based compounds, 5,5′-di(pyridin-3-yl)-2,2′-bithiophene (T1) and 5,5′-di(pyridin-4-yl)-2,2′-bithiophene (T2) combined with eight coformers. Molecular electrostatic potential surface (MEPS) calculations were used to guide the cocrystallization outcomes, which were compared to experimentally observed results via IR, NMR, TGA, and single-crystal X-ray diffraction. The two targets cocrystallized with all the eight coformers and single crystals were obtained in eight instances. The single-crystal structure analysis results matched the MEPS predicted homomeric and heteromeric synthons in all the cases except T2:4-hydroxybenzoic acid. The differences observed in the hydrogen-bond interactions for these combinations provided a promising indication of using cocrystallization as a tool to manipulate the target compounds’ electronic and optical properties. Synthon ; Thiophene ; Hydrogen bond ; Single crystal ; Crystal engineering ; Crystallography ; Organic semiconductor ; Homomeric ; Crystal structure ; Materials science ; Chemistry ; Stacking ; Molecule ; Stereochemistry ; Organic chemistry Crystallography and molecular interactions ; Crystallization and Solubility Studies ; Energetic Materials and Combustion
Authors: Rangsan Panyathip | Thanakrit Sintiam | SORAWIT WEERAPONG | Athipong Ngamjarurojana | Pisist Kumnorkaew | Supab Choopun | Sukrit Sucharitakul
Source: Surface Review and Letters (article, 2021-10-09)
Field: Materials Science — Materials Chemistry

ELECTROLYTIC EFFECT ON GROWTH OF GRAPHENE QUANTUM DOTS VIA ELECTROCHEMICAL PROCESS Quantum dots (QDs) are materials grown in confined dimension also known as 0D materials. QDs can be synthesized in many shapes and forms through various methods making the materials extremely versatile and can be fine-tuned for appropriate applications. Among the potentially scalable methods, Electrochemical process is considered as one of the top-down approaches with the highest potential for scalability and easy-to-process methodology while electrolyte and pH level can play various important roles on the final product. In this work, we grew and studied the effect of electrolytic solution in the growth of graphene quantum dots (GQDs) in colloidal forms using cheap graphite as precursor in KCl and NaOH as electrolytes in various concentrations. It can be inferred from our results that when KCl and NaOH were used in combination with citric acid, the optoelectrical properties and hydrodynamic properties of the resulting growth can be fine-tuned to match the required applications. [Formula: see text] electronics excitation was identified with small tunability of 487–500[Formula: see text]nm wavelength while the hydrodynamic size varied from 80–140[Formula: see text]nm with resulting pH range from 3.0–9.5 adjustable to appropriate applications, while the TEM results showed physical particle size of 1.7–3.7[Formula: see text]nm. Electrolyte ; Quantum dot ; Graphene ; Electrochemistry ; Materials science ; Nanotechnology ; Particle size ; Colloid ; Nanoparticle ; Chemical engineering ; Electrode ; Chemistry ; Physical chemistry Carbon and Quantum Dots Applications ; Quantum Dots Synthesis And Properties ; Graphene research and applications
Authors: Tobias Foller | Rahman Daiyan | Xiaoheng Jin | Josh Leverett | Hangyel Kim | Richard F. Webster | Jeaniffer E. Yap | Xinyue Wen | Aditya Rawal | Kanishka DeSilva | Masamichi Yoshimura | Heriberto Bustamante | Shery L. Y. Chang | Priyank V. Kumar | Yi You | Gwan‐Hyoung Lee | Rose Amal | Rakesh Joshi
Source: Materials Today (preprint, 2021-09-09)
Field: Materials Science — Materials Chemistry

Enhanced graphitic domains of unreduced graphene oxide and the interplay of hydration behaviour and catalytic activity Graphene ; Oxide ; Catalysis ; Materials science ; Nanotechnology ; Chemical physics ; Diffusion ; Thermal stability ; Transmission electron microscopy ; Chemical engineering ; Chemistry ; Thermodynamics ; Physics ; Organic chemistry Graphene research and applications ; Advancements in Battery Materials ; Nanomaterials for catalytic reactions
Authors: R. Teruel-Juanes | B. Pascual-José | Robert Graf | José Antonio Reina | Marta Giamberini | A. Ribes‐Greus
Source: Polymers (article, 2021-06-13)
Field: Materials Science — Polymers and Plastics

Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as γ, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (α<sub>Tg</sub>). Only after that, clearing transition (α<sub>Clear</sub>) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups. Epichlorohydrin ; Copolymer ; Materials science ; Dendrimer ; Glass transition ; Polymer chemistry ; Substituent ; Dielectric ; Polymer ; Chemical engineering ; Chemistry ; Organic chemistry ; Composite material Conducting polymers and applications ; Membrane Separation and Gas Transport ; Synthesis and properties of polymers
Authors: Ting Xu | Ning Chen | Zhimin He | Pengwei Yu | Wangqiang Shen | Takeshi Akasaka | Xing Lü
Source: Chemistry - A European Journal (article, 2021-04-25)
Field: Chemistry — Organic Chemistry

Morphology Engineering of Fullerene[C<sub>70</sub>] Microcrystals: From Perfect Cubes, Defective Hoppers to Novel Cruciform‐Pillars Controlled crystallization of fullerene molecules into ordered molecular assemblies is important for their applications. However, the morphology engineering of fullerene[C<sub>70</sub> ] assemblies is challenging, and complicated architectures have rarely been reported due to the low molecular symmetry of C<sub>70</sub> molecules, which makes their crystallization difficult to control and the low production yield as well. Herein, with the assistance of solvent intercalation, a general reprecipitation approach is reported to prepare morphologically controllable C<sub>70</sub> microcrystals with mesitylene as a good solvent and n-propanol as a poor solvent in one solvent system without replacing specific solvents. A series of C<sub>70</sub> microcrystals with high uniformity from perfect cubes and defective hoppers to novel cruciform-pillars are obtained by intentionally tuning C<sub>70</sub> concentration and the volume ratio of mesitylene to n-propanol. Among them, novel cruciform-pillar-shaped microcrystals are obtained for the first time by further decreasing the amount of mesitylene in the solvent-intercalated microcrystals. Notably, the C<sub>70</sub> concentration is a key parameter for the selective growth of C<sub>70</sub> hopper, rather than the volume ratio of mesitylene to n-propanol. Interestingly, the hopper-shaped microcrystals exhibit excellent photoluminescence properties relative to those of cubes and cruciform-pillars owing to the enhanced light absorption, proving their potential applications in optoelectronic devices. This study offers new insights into the morphology-controlled synthesis of other micro/nanostructured organic microcrystals and the fine tuning of photoluminescence properties of organic crystals. Mesitylene ; Photoluminescence ; Solvent ; Crystallization ; Materials science ; Cruciform ; Chemical engineering ; Fullerene ; Crystallography ; Molecule ; Nanotechnology ; Chemistry ; Toluene ; Organic chemistry ; Optoelectronics ; Composite material Fullerene Chemistry and Applications ; Graphene research and applications ; Carbon Nanotubes in Composites
Authors: Alireza Zare | B. Pascual-José | Silvia De la Flor | A. Ribes‐Greus | Xavier Montané | José Antonio Reina | Marta Giamberini
Source: Polymers (article, 2021-10-14)
Field: Materials Science — Polymers and Plastics

Membranes for Cation Transport Based on Dendronized Poly(epichlorohydrin-co-ethylene oxide). Part 1: The Effect of Dendron Amount and Column Orientation on Copolymer Mobility Dendronized polyethers give rise to columnar LC structures which can successfully act as cation transport materials. Therefore, we prepared two different materials, based on Poly(epichlorohydrin-co-ethylene oxide) (PECH-co-EO) grafted with methyl 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, containing 20% or 40% modified units, respectively. The obtained polymers were characterized by differential scanning calorimetry (DSC), X-ray diffraction and optical microscopy between crossed polars (POM) and compared to the unmodified PECH-co-EO. In order to reach efficient transport properties, homeotropically oriented membranes were prepared by a fine-tuned thermal annealing treatment and were subsequently investigated by dynamic mechanical thermal analysis (DMTA) and dielectric thermal analysis (DETA). We found that the presence of the dendrons induces a main chain partial crystallization of the polyether chain and coherently increases the polymer Tg. This effect is more evident in the oriented membranes. As for copolymer orientation upon annealing, the cooling rate and the annealing temperature were the most crucial factors. DMTA and DETA confirmed that grafting with the dendron strongly hinders copolymer motions, but did not show great differences between unoriented and oriented membranes, regardless of the amount of dendrons. Materials science ; Copolymer ; Epichlorohydrin ; Dynamic mechanical analysis ; Membrane ; Polymer chemistry ; Differential scanning calorimetry ; Chemical engineering ; Thermal analysis ; Polymer ; Ethylene oxide ; Annealing (glass) ; Dendrimer ; Glass transition ; Composite material ; Chemistry ; Thermal Dendrimers and Hyperbranched Polymers ; Fuel Cells and Related Materials ; Conducting polymers and applications
Authors: Liyong Cui | Hang Yin
Source: New Journal of Physics (article, 2021-07-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Evanescent wave induced polarization-insensitive self-organization of stratified single-negative materials Abstract Optical fields can induce optical forces between macroscopic objects, giving rise to different structures. Through rigorous calculation, we show that a collection of single negative slabs which possesses either negative permittivity or negative permeability (i.e. ε &lt; 0, μ &gt; 0 or ε &gt; 0, μ &lt; 0) in water can be self-organized into one-dimensional photonic crystals, due to the coupling of propagating wave and evanescent wave. We further demonstrated that the optical binding is irrespective of the polarization and angle of the incident plane wave. We call such a phenomenon—polarization-insensitive optical binding. We also demonstrate that polarization-insensitive optical binding can be achieved on microscale and millimeter scale. Polarization and angle insensitive band edge is the key to achieve polarization and angle insensitive optical binding. This work provides a new strategy to tailor the photonic crystals containing single negative materials towards the development of fine-tuning optical devices. Physics ; Polarization (electrochemistry) ; Optics ; Microscale chemistry ; Evanescent wave ; Photonics ; Photonic crystal ; Optoelectronics Metamaterials and Metasurfaces Applications ; Photonic Crystals and Applications ; Plasmonic and Surface Plasmon Research
Authors: Jiao He | Chenglong Deng | Cunfa Sun | Xiaoxiao Zhang | Ying Cui | Sheng-Hui Wu | Geng‐Geng Luo
Source: Chemical Communications (article, 2021-12-30)
Field: Materials Science — Materials Chemistry

Controllable spontaneous resolution in ultrasmall Cu–Ag bimetallic cluster ion pairs from achiral components Bimetallic cluster ion pairs containing a quaternary phosphonium and an ultrasmall Cu<sub>2</sub>Ag<sub>3</sub> anionic cluster protected by thiolates: (PPh<sub>3</sub>R'')[Cu<sub>2</sub>Ag<sub>3</sub>(SR')<sub>6</sub>] (R'SH = cyclohexylthiol (CySH), R'' = Ph, 1; Me, 2; Et, 3; Pr, 4; R'SH = <i>tert</i>-butylthiol (<sup><i>t</i></sup>BuSH) and R'' = Ph, 5) were reported. Without any chiral source, 1 crystallizes as conglomerate crystals with homochiral packings and spontaneous resolution occurs, while four other clusters 2-5 crystallize as racemic crystals with heterochiral packings. These results indicate that racemic and homochiral crystallization in the cluster system could be controlled through fine-tuning internal achiral structural components. Bimetallic strip ; Cluster (spacecraft) ; Crystallography ; Crystallization ; Phosphonium ; Ion ; Chemistry ; Resolution (logic) ; Stereochemistry ; Catalysis ; Polymer chemistry ; Organic chemistry Nanocluster Synthesis and Applications ; Magnetism in coordination complexes ; Metal-Organic Frameworks: Synthesis and Applications
Authors: L.E.L. Silva | J. Caro Patiño | A. M. Gomes
Source: Journal of Physics Condensed Matter (article, 2021-02-22)
Field: Materials Science — Materials Chemistry

On the structural and thermo-magnetic study of the magnetocaloric Heusler alloy Ni <sub>2</sub> Mn <sub> 1- <i>x</i> </sub> Cu <sub> <i>x</i> </sub> Ga <sub>0.8</sub> Al <sub>0.2</sub> Full Heusler alloys present martensitic transition and shape memory effect related phenomena and several technological applications can be envisaged. One promising area is the magnetocaloric effect (MCE) as the magnetic and structural transitions combine to produce a large isothermal entropy and adiabatic temperature change useful for heating and cooling applications. In this work, we study a Ni-(Mn, Cu)-(Ga, Al) Heusler alloy family which has a giant MCE when the chemical composition is fine-tuned to bring the temperature of the second-order magnetic transition close the first-order structural one. Our results show that, for a certain range of copper concentration, the samples show interesting physical properties captured by calorimetric, microscopy imaging, and magnetization measurements, leading to a high MCE with minimized hysteresis. Magnetic refrigeration ; Materials science ; Alloy ; Isothermal process ; Magnetic shape-memory alloy ; Magnetization ; Adiabatic process ; Condensed matter physics ; Magnetic hysteresis ; Shape-memory alloy ; Martensite ; Hysteresis ; Copper ; Metallurgy ; Thermodynamics ; Magnetic field ; Microstructure ; Magnetic anisotropy Shape Memory Alloy Transformations ; Magnetic and transport properties of perovskites and related materials ; Creativity in Education and Neuroscience
Authors: Jia-Wen Hong | Yi-Qing Jian | Yin-Ping Liao | Hsiang-Ho Hung | Tzu‐Yen Huang | Andrew Nelson | I‐Yu Tsao | Chun‐Ming Wu | Ya‐Sen Sun
Source: Langmuir (article, 2021-10-25)
Field: Materials Science — Materials Chemistry

Distributions of Deuterated Polystyrene Chains in Perforated Layers of Blend Films of a Symmetric Polystyrene<i>-block-</i>poly(methyl methacrylate) We have examined the spatial distributions of polymer chains in blend films of weakly segregated polystyrene<i>-block-</i>poly(methyl methacrylate) [P(S-<i>b</i>-MMA)] and deuterated polystyrene (dPS). By fine-tuning the composition (ϕ<sub>PS+dPS</sub> = 63.8 vol %) of the total PS/dPS component and annealing temperature (230 and 270 °C), P(S-<i>b</i>-MMA)/dPS blend films mainly form perforated layers with a parallel orientation (hereafter PLs<sup>//</sup>). The distributions of dPS in PLs<sup>//</sup> were probed by grazing-incidence small-angle neutron scattering (GISANS) and time-of-flight neutron reflectivity (ToF-NR). GISANS and ToF-NR results offer evidence that dPS chains preferentially locate at the free surface and within the PS layers for blend films that were annealed at 230 °C. Upon annealing at 270 °C, dPS chains distribute within PS layers and perforated PMMA layers. Nevertheless, dPS chains still retain a surface preference for thin films. In contrast, such surface segregation of dPS chains is prohibited for thick films when annealed at 270 °C. Polystyrene ; Materials science ; Methyl methacrylate ; Annealing (glass) ; Polymer ; Deuterium ; Polymer chemistry ; Poly(methyl methacrylate) ; Neutron scattering ; Methacrylate ; Scattering ; Analytical Chemistry (journal) ; Composite material ; Chemical engineering ; Optics ; Chemistry ; Polymerization ; Organic chemistry Block Copolymer Self-Assembly ; Polymer crystallization and properties ; Rheology and Fluid Dynamics Studies
Authors: Kalaivani Vivehananthan | W.H. De Silva
Source: Advances in Technology (article, 2021-08-31)
Field: Materials Science — Materials Chemistry

Effect of Different Process Parameters on the formation of Silver Nanoparticles using Crude and Modified Neem (Azadirachta indica) Leaf Extracts In recent times, the biosynthesis of nanoparticles, which has led to significant growth in the field of nanotechnology. The use of plant extracts has become an impetus in this field as it is a simple and eco-friendly method. This study was an attempt to study different parameters in biosynthesis of silver nanoparticles using Azadirachta indica (Neem) leaf extracts. Four different process parameters such as concentrations of neem leaf extract, types of neem leaf extract, mixing ratios and the reaction time period were investigated on the formation of silver nanoparticles. Initially, the formation of silver nanoparticles was detected by the visual observation. Then, the synthesized silver nanoparticles were characterized using UV-Visible spectroscopy and scanning electron microscopy (SEM). The change of color from yellow to reddish brown color confirmed the formation of silver nanoparticles. The silver surface plasmon resonance (SPR) band obtained in the expected visible range of UV-Visible spectroscopy confirmed the synthesis of the nanoparticles. SEM images showed that silver nanoparticles are roughly spherical and of uniform particle size, and the average particle size is 100 nm. Further, the maximum absorbance of SPR band was considerably varied with different process parameters used in the present study. The UV-Visible spectra of 2.5 g/100 mL of crude neem leaf extract without any dilution showed maximum absorbance in the expected range with the mixing ratio of (Neem and AgNO3) 1:8. However, the maximum absorbance of modified neem leaf extracts (pH 10) resulted lower in value than the crude extracts in the 20 times diluted sample with the mixing ratio of 1:9. Moreover, modified extract with UV radiation exposure increased the absorbance in the expected visible range. It concludes that fine tuning of the bioprocess parameters would enhance nanoparticle synthesis. Azadirachta ; Absorbance ; Silver nanoparticle ; Surface plasmon resonance ; Nanoparticle ; Particle size ; Scanning electron microscope ; Nuclear chemistry ; Materials science ; Ultraviolet visible spectroscopy ; Chemistry ; Spectroscopy ; Analytical Chemistry (journal) ; Chromatography ; Botany ; Nanotechnology ; Organic chemistry ; Biology Nanoparticles: synthesis and applications
Authors: Muhammad Taha Sultan | Kristina Ignatova | Einar B. Thorsteinsson | F. Magnus | Unnar B. Arnalds
Source: Journal of Physics D Applied Physics (article, 2021-07-14)
Field: Materials Science — Materials Chemistry

Structural and electrical properties of V <sub>2</sub> O <sub>3</sub> thin films on <i>c</i> -plane Al <sub>2</sub> O <sub>3</sub> fabricated by reactive-HiPIMS and dcMS techniques Abstract The study presents the synthesis of epitaxial V 2 O 3 thin films on c -plane Al 2 O 3 substrates by reactive high-power impulse (HiPIMS) and direct current (dcMS) magnetron sputtering. The results reveal that for fixed deposition conditions and discharge power, well defined epitaxial layers can be attained using both HiPIMS and dcMS. For dcMS we observe the formation of these epitaxial films down to flow rate values of 1.3 sccm while for HiPIMS we observe an extended operation window down to much lower oxygen flow of 0.5 sccm without sacrificing the structural quality of the films. Furthermore, the effect of varying HiPIMS discharge parameters i.e. repetition frequency and average power for fixed O 2 flow setting, were explored in order to determine their effect on the structural quality and electrical characteristics of the films. The magnitude of the metal–insulator transition (MIT) and the transition temperature is correlated to the film stoichiometry which can be fine-tuned by mapping the HiPIMS discharge parameters, displaying a total change in resistance of ∼7 decades over the studied temperature range. The MIT temperature and magnitude obtained for films fabricated by HiPIMS, even for low O 2 flow settings (down to 0.6–0.5 sccm), displayed superior characteristics compared to films fabricated by dcMS where a minimum O 2 flow of 1.3 sccm was needed. High-power impulse magnetron sputtering ; Thin film ; Materials science ; Crystallography ; Sputtering ; Analytical Chemistry (journal) ; Chemistry ; Nanotechnology ; Sputter deposition ZnO doping and properties ; Gas Sensing Nanomaterials and Sensors ; Electronic and Structural Properties of Oxides