Electrodeposition of Aluminum Coatings from AlCl3-NaCl-KCl Molten Salts with TMACl and NaI Additives

The Al coatings achieved via electrodeposition on a Cu electrode from AlCl3-NaCl-KCl (80–10–10 wt.%) molten salts electrolyte with Tetramethylammonium Chloride (TMACl) and Sodium Iodide (NaI) additives is reported. The effect of the two additives on electrodeposition were investigated by cyclic voltammetry (CV), chronopotentiometry (CP), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results reveal that compact and smooth Al coatings are obtained at 150 °C by the electrodeposition process from the electrolyte with 1% TMACl and 10% NaI. The Al coatings exhibit great corrosion resistance close to that of pure Al plate, with a corrosion current of 3.625 μA. The average particle size is approximately 2 ± 1 μm and the average thickness of the Al layer is approximately 7 ± 2 μm. The nucleation/growth process exhibits irrelevance with TMACl or NaI during the electrodeposition of Al. TMACl cannot affect and improve the electrodeposition effectively. However, the addition of TMACl and NaI can intensify the cathodic polarization, producing an inhibition of Al deposition, and contribute to form uniform Al deposits. This can increase the conductivity and facilitate in refining the size of Al particles, contributing to forming a continuous, dense and uniform layer of Al coating, which can be used as effective additives in molten salts electrolyte.

A Biomimetic Approach to Increasing Soft Actuator Performance by Friction Reduction

While increasing power output is the most straight-forward solution for faster and stronger motion in technology, sports, or elsewhere, efficiency is what separates the best from the rest. In nature, where the possibilities of power increase are limited, efficiency of motion is particularly important; the same principle can be applied to the emerging biomimetic and bio-interacting technologies. In this work, by applying hints from nature, we consider possible approaches of increasing the efficiency of motion through liquid medium of bilayer ionic electroactive polymer actuations, focusing on the reduction of friction by means of surface tension and hydrophobicity. Conducting polyethylene terephthalate (PET) bilayers were chosen as the model actuator system. The actuation medium consisted of aqueous solutions containing tetramethylammonium chloride and sodium dodecylbenzenesulfonate in different ratios. The roles of ion concentrations and the surface tension are discussed. Hydrophobicity of the PET support layer was further tuned by adding a spin-coated silicone layer to it. As expected, both approaches increased the displacement—the best results having been obtained by combining both, nearly doubling the bending displacement. The simple approaches for greatly increasing actuation motion efficiency can be used in any actuator system operating in a liquid medium.

Catalytic Conversion of Sugarcane Bagasse into 5-Hydroxymethylfurfural

Furan derivatives especially 5-Hydroxymethylfurfural has recently been regarded as one important precursor for the production of biofuels and biobased compounds. Aims: The aim of this study was to convert sugarcane bagasse into 5-hydroxymethylfurfural using Tetrabutylammonium bromide, Tetramethylammonium chloride and metal chlorides (chromium chloride, copper chloride, ferric chloride and cobalt chloride) in dimethylsulphoxide; using different reaction time and temperatures. Study Design: The design of this study includes preparation of two different systems of catalyst to convert sugarcane bagasse into 5-hydroxymethylfurfural. Place and Duration of Study: This study conducted at Department of Applied and Industrial Chemistry, International University of Africa- Sudan, between 2017 and 2019. Methodology: Two different catalytic systems were prepared to convert sugarcane bagasse into 5-hydroxymethylfurfaural, the first system Tetrabutylammonium bromide and metal chlorides (Chromium chloride, copper chloride, ferric chloride and cobalt chloride) in dimethyl sulphoxide; the second system tetrametheylammonium chloride and same metal chlorides in dimethylsulphoxide. The conversion of sugarcane bagasse was conducted at temperatures 100, 130 and 150°C; in addition to reaction times 60, 90 and 120 min. Results: The obtained results indicated that the yield of 5-hydroxymethylfurfural was high 53.41% at 150°C and 120 min reaction time when chrome chloride was used in Tetrabutylammonium bromide and dimethylsulphoxide as co-solvent; although the highest yield 89.23%, was noted also at same condition, when chromium chloride was used in Tetramethylammonium chloride and dimethylsulphoxide as co-solvent. Conclusion: Based on these results chromium chloride was considered the best catalyst for yielding 5-hydroxymethylfurfural from sugarcane bagasse in both Tertabutylammonium bromide and Tetramethylammonium chloride; but is best in Tetramethylammonium chloride.

Synthesis and Luminescence of Optical Memory Active Tetramethylammonium Cyanocuprate(I) 3D Networks

The structures of three tetramethylammonium cyanocuprate(I) 3D networks [NMe4]2[Cu(CN)2]2•0.25H2O (1), [NMe4][Cu3(CN)4] (2), and [NMe4][Cu2(CN)3] (3), (Me4N = tetramethylammonium), and the photophysics of 1 and 2 are reported. These complexes are prepared by combining aqueous solutions of the simple salts tetramethylammonium chloride and potassium dicyanocuprate. Single-crystal X-ray diffraction analysis of complex 1 reveals {Cu2(CN)2(μ2-CN)4} rhomboids crosslinked by cyano ligands and D3h {Cu(CN)3} metal clusters into a 3D coordination polymer, while 2 features independent 2D layers of fused hexagonal {Cu8(CN)8} rings where two Cu(I) centers reside in a linear C∞v coordination sphere. Metallophilic interactions are observed in 1 as close Cu⋯Cu distances, but are noticeably absent in 2. Complex 3 is a simple honeycomb sheet composed of trigonal planar Cu(I) centers with no Cu…Cu interactions. Temperature and time-dependent luminescence of 1 and 2 have been performed between 298 K and 78 K and demonstrate that 1 is a dual singlet/triplet emitter at low temperatures while 2 is a triplet-only emitter. DFT and TD-DFT calculations were used to help interpret the experimental findings. Optical memory experiments show that 1 and 2 are both optical memory active. These complexes undergo a reduction of emission intensity upon laser irradiation at 255 nm although this loss is much faster in 2. The loss of emission intensity is reversible in both cases by applying heat to the sample. We propose a light-induced electron transfer mechanism for the optical memory behavior observed.