223 research outputs found

    catena-Poly[[(ethanol-κO)sodium(I)]-di-μ-aqua-[(rac-2′-hydr­oxy-1,1′-binaphthyl-2-yl phosphato-κO)sodium]-tri-μ-aqua]

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    The asymmetric unit of the polymeric title compound, [Na2(C20H13O5P)(C2H6O)(H2O)5]n, consists of two NaI ions, one 2′-hydr­oxy-1,1′-binaphthyl-2-yl phosphate anion, one ethanol ligand and five water molecules of crysallization. Each NaI ion has a distorted octa­hedral coordination geometry. The phosphate anion coordinates to one NaI ion and the ethanol mol­ecule coordinates to the other. The five water mol­ecules bridge the NaI ions, forming an inorganic chain structure along the b axis. The chains are connected by O—H⋯O hydrogen bonds into an organic–inorganic hybrid layer parallel to (001)

    Improvement of the guiding performances of near infrared organic/inorganic channel waveguides

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    New sol-gel derived organic/inorganic hybrid single mode waveguides devices have been developed for telecommunication applications in the two near infrared windows at 1310 and 1550 nm. The overall procedure of fabrication of these devices is described and the refractive indices of the guiding, the buffer and the protective layers are adjusted by a precise control of the materials' composition. Due to the improvement of the composition of the guiding layer, the attenuation losses are significantly decreased to 0.8 dB/cm and 2dB/cm at respectively 1310 and 1550 nm

    Stability and solid-state polymerization reactivity of imidazolyl- and benzimidazolyl-substituted diacetylenes: pivotal role of lattice water

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    International audience1,6-Bis(1-imidazolyl)-2,4-hexadiyne (1) and1,6-bis(1-benzimidazolyl)-2,4-hexadiyne (5) have beenpreparedby a novel method that consists in refluxing excess imidazole and benzimidazole with 2,4-hexadiyne-1,6-diol bis(p-toluenesulfonate),pTS (3). This procedure is a viable alternative to the widely used Hay coupling protocol in case the target diyne possesses substituents capable of deactivating the copper catalyst by complexation. Diyne1crystallizes as a hydrate,1?H2O(2). For this compound, water is essential toachieve a crystalline material, and attempts to obtain crystals without included solvent were unsuccessful. In the structure of2, the organic fragments organize around the water molecule and interact with it through a dense network of hydrogen bonds. The CMC-CMC moieties are not oriented suitably for topochemical polymerization, and when trying to alter the organizationof the crystal by heating so as to induce polymerization, water is lost in an abrupt fashion that leads to instantaneous decomposition into polyaromatic-like species. Similar results were observed when water was removedin vacuo at room temperature. The benzimidazole-containing compound can be crystallized with water molecules (4)orwithout(5). X-ray crystallography shows that the structure of 5is organized by numerous C-H...N, C-H...p,andimidazolyl...imidazolyl p-p interactions. The diacetylene molecules almost have the right arrangement for topochemical polymerization, withpossibly reactingCMC-CMC fragments not beingparallel, a rare situation indiacetylene chemistry. Yet, experiments showthat topochemical polymerizationdoes not occur. Incorporationofwater in the lattice of5leads toa solvate that is topochemically reactive. Unlike2, however, water molecules in 4are not isolated but are organized as ribbons. Spectroscopic characterization of the polymer of4indicates that it is a blue phase polymer, with water coordinated to it. This study shows that it is possible to use water, and more generally solvent molecules, to transform a nonreactive diacetylene into a reactive one, even though this approach is less predictable than the cocrystal approach developed by Fowler, Lauher, and Goroff. The solvate approach is simple to implement, quite versatile because of the large rangeof solvents available, andonedoes not face theproblemof having to remove the host in case one needs to recover the polymer. Previous studies describing a similar approach are scarce

    Photopatternable ionogels for electrochromic applications

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    This work describes the development of photopatternable ionogels based on a hybrid organic/inorganic sol–gel material and both phosphonium (trihexyltetradecylphosphonium dicyanamide [P6,6,6,14][dca], trihexyltetradecylphosphonium bis(trifluoromethanesulfonyl)-amide [P6,6,6,14][NTf2]) and imidazolium (1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate [emIm][FAP]) room temperature ionic liquids (RTILs). Ionogels were prepared via a two step process with the RTIL content varied between 40 and 80 w/w%, and characterised via Raman and Electrochemical Impedance Spectroscopy. 1 and 2 photon polymerisation was performed on the hybrid ionogels using photolithography, resulting in three dimensional structures that were characterised using scanning electron microscopy. Electrochromic ionogels were prepared by addition of ethyl viologen dibromide (EV) to an ionogel containing [emIm][FAP] and hybrid sol–gel material. This composition was photopolymerised on ITO electrodes by UV irradiation and subsequentially characterised via UV/Vis spectroelectrochemistry. It was also possible to fabricate a solid state electrochromic device based on EV and switch between the colourless (oxidised) and blue (reduced) forms using a perturbation signalof 1 V

    Graphene-doped photo-patternable ionogels: tuning of conductivity and mechanical stability of 3D microstructures

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    This work reports for the first time the development of enhanced conductivity, graphene- doped photo-patternable hybrid organic-inorganic ionogels and the effect of the subsequent materials condensation on the conductivity and mechanical stability of three- dimensional microstructures fabricated by multi-photon polymerisation (MPP). Ionogels were based on photocurable silicon/zirconium hybrid sol-gel materials and phosphonium (trihexyltetradecylphosphonium dicyanamide [P6,6,6,14][DCA] ionic liquid (IL). To optimise the dispersion of graphene within the ionogel matrices, aqueous solutions of graphene were prepared, as opposed to the conventional graphene powder approach, and employed as catalysts of hydrolysis and condensation reactions occurring in the sol-gel process. Ionogels were prepared via a two step process by varying the hydrolysis degree from 25 to 50%, IL content between 0-50 w/w%, and the inorganic modifier (zirconate complex) concentration from 30 to 60 mol.% against the photocurable ormosil and they were characterised via Raman, Electrochemical Impedance Spectroscopy and Transmission Electron Microscopy. MPP was performed on the hybrid ionogels, resulting in three- dimensional microstructures that were characterised using scanning electron microscopy. It is clearly demonstrated that the molecular formulation of the ionogels, including the concentration of graphene and the zirconate network modifier, play a critical role in the conductivity of the ionogels and influence the resulting mechanical stability of the fabricated three-dimensional microstructures. This work aims to establish for the first time the relationship between the molecular design and condensation of materials in the physico-chemistry and dynamic of ionogels

    An overview of progress in electrolytes for secondary zinc-air batteries and other storage systems based on zinc

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    The revived interest and research on the development of novel energy storage systems with exceptional inherent safety, environmentally benign and low cost for integration in large scale electricity grid and electric vehicles is now driven by the global energy policies. Within various technical challenges yet to be resolved and despite extensive studies, the low cycle life of the zinc anode is still hindering the implementation of rechargeable zinc batteries at industrial scale. This review presents an extensive overview of electrolytes for rechargeable zinc batteries in relation to the anode issues which are closely affected by the electrolyte nature. Widely studied aqueous electrolytes, from alkaline to acidic pH, as well as non-aqueous systems including polymeric and room temperature ionic liquids are reported. References from early rechargeable Zn-air research to recent results on novel Zn hybrid systems have been analyzed. The ambition is to identify the challenges of the electrolyte system and to compile the proposed improvements and solutions. Ultimately, all the technologies based on zinc, including the more recently proposed novel zinc hybrid batteries combining the strong points of lithium-ion, redox-flow and metal-air systems, can benefit from this compilation in order to improve secondary zinc based batteries performance.Basque Country University (ZABALDUZ2012 program), and the Basque Country Government (Project: CIC energiGUNÉ16 of the ELKARTEK program) and the European Commission through the project ZAS: “Zinc Air Secondary innovative nanotech based batteries for efficient energy storage” (Grant Agreement 646186
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