47 research outputs found

    From test tube to Turner - The role of the chemist in art

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    Most modern art galleries arrange their collections in chronological order and to the average viewer it often the changes in style, fashion or subject matter that is indicative of the passage of time. Far less noted, although possibly more obvious is the change in paint which occurred. Ultimately it is the evolution of chemical techniques that is responsible for these developments. In this article, the major changes in chemical techniques and elemental discovery will be mapped onto the subsequent development of pigments and their use in artworks

    Redox fusion of metal particles using deep eutectic solvents.

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    Alternating anodic and cathodic current pulses have been applied to a metal powder on an electrode surface to fuse the particles together. It is shown that homogeneous films can be electroformed with different morphologies depending on the size of the powder and the experimental conditions

    Redox fusion of metal particles using deep eutectic solvents.

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    Alternating anodic and cathodic current pulses have been applied to a metal powder on an electrode surface to fuse the particles together. It is shown that homogeneous films can be electroformed with different morphologies depending on the size of the powder and the experimental conditions

    Facile fabrication of nickel nanostructures on a copper-based template via a galvanic replacement reaction in a deep eutectic solvent

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    We describe an unusual galvanic replacement process for facile synthesis of nickel nanostructures by using Cu as a sacrificial template in a deep eutectic solvent (DES), ethaline. This replacement process occurred through a galvanic exchange of [NiCl4]2 − ions in ethaline at 353 K with an immersed Cu substrate, which acted as both reactive template and reductant. The mechanism for this replacement reaction and the morphology and topography evolution process of the nickel nanostructures were investigated. This facile preparation method performed in ethaline provides a novel way to fabricate nickel nanostructures with particulate or porous architecture on a copper-based template

    Effect of Electrolyte Concentration on the Viscosity and Voltammetry of Supercritical Solutions

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    The viscosity of a supercritical electrolyte solution is measured for the first time using a modified quartz crystal microbalance, and it is shown that ionic solvation leads to a significant structuring of the solvent and an appreciable increase in solution viscosity. Voltammetric investigations in the electrolyte solutions are used to confirm the magnitude of the viscosity changes, and these account for the appreciably lower than expected peak currents

    Facile fabrication of nickel nanostructures on a copper-based template via a galvanic replacement reaction in a deep eutectic solvent

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    We describe an unusual galvanic replacement process for facile synthesis of nickel nanostructures by using Cu as a sacrificial template in a deep eutectic solvent (DES), ethaline. This replacement process occurred through a galvanic exchange of [NiCl4]2 − ions in ethaline at 353 K with an immersed Cu substrate, which acted as both reactive template and reductant. The mechanism for this replacement reaction and the morphology and topography evolution process of the nickel nanostructures were investigated. This facile preparation method performed in ethaline provides a novel way to fabricate nickel nanostructures with particulate or porous architecture on a copper-based template

    O-acetylation of cellulose and monosaccharides using a zinc based ionic liquid

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    The efficient O-acetylation of monosaccharides and cellulose is demonstrated using a Lewis acidic ionic liquid based on choline chloride and zinc chloride

    Electropolishing of nickel and cobalt in deep eutectic solvents

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    Electropolishing is a common method for decreasing surface roughness and removing surface irregularities. In this paper the electropolishing of nickel and cobalt are successfully demonstrated in a deep eutectic solvent, comprising a 2:1 molar mixture of ethylene glycol and choline chloride. Voltammetric and electrochemical impedance studies were used to characterise the polishing mechanism and show that film formation occurs prior to polishing. Scanning electron microscopy and atomic force microscopy were used to characterise the morphology before and after polishing and 3D optical microscopy was used in-situ to observe film formation during polishing. This study shows that the impact of film formation and subsequently mass transport are responsible for electropolishing of both metals in the choline chloride-based ionic liquid

    Improving the Conductivity of Graphite-Based Lithium-Ion Battery Anodes Using Polyaniline–Alginate Blends

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    This investigation shows the effect of blending sodium alginate (NaAlg) and a conducting polymer, polyaniline (PANI), in lithium-ion battery (LIB) anodes. We demonstrate here that inclusion of the PANI into the binder improves the connectivity of the composite, resulting in better performance. Additionally, the blends are easily formulated without sophisticated methods or additional equipment. When these binders were combined into electrodes, the conductivity rose by between 3- and 5-fold compared with the unmodified NaAlg, depending on the PANI loading. The conducting polymer did not significantly change the thermal stability or cycling of the cells, but it did improve the Coulombic efficiency. During electrochemical testing, it was found that cells containing PANI within the binders exhibited evidence of essential processes, such as SEI formation and lithium intercalation. Evidence of side reactions was observed, predicted to be the lithiation of PANI to create lithium emeraldinate within the polymeric regions, which could increase the Coulombic efficiency of the cells and allow for the decrease in impedance contributions after extensive cycling. Capacities and rate capabilities comparable to anodes prepared using graphite and commercial binders PVDF and CMC/SBR were also observed. Crucially, after cycling, the NaAlg/PANI binder could be fully removed from the active material with mild ultrasonic agitation in water

    Cationic functionalisation of cellulose using a choline based ionic liquid analogue

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    The efficient cationic functionalisation of cellulose is demonstrated using an ionic liquid analogue, based on a eutectic mixture of a choline chloride derivative and urea, which acts as both solvent and reagent. It was determined that all the available hydroxyl groups on cellulose had been modified
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