Soft chemistry

Sol-gel chemistry, molecular precursor methods and metal-organic decomposition (MOD) techniques have been selected for their flexibility, scalability and low cost. These wet chemical routes are coupled with various shaping techniques : spin-coating, dip-coating, spray-drying, spray-pyrolysis for the preparation of thin films or nanoparticles.

[bleu marine]Dip-coating : La2Zr2O7 (LZO) or CeO2 buffer layer epitaxied on textured Ni substrates before the final deposition of YBa2Cu3O7 (YBCO) superconducting coating.[/bleu marine] The Supraconducteurs - MCBT group makes textured YBa2Cu3O7 superconductors, that are produced by epitaxy, grain by grain, with an appropriate stacking of oxide films, themselves epitaxied on a textured metal substrate. Each step, deposition, nucleation and growth, is controlled separately. The resulting flat tapes are able to carry high superconducting currents (1 MA/cm2 at 77 K under self-field). This method will be adapted to a continuous process that will make possible to manufacture longer samples involving a new tube shaping (coll. with Nexans France and ArcelorMittal Stainless & Nickel Alloys).

The MatONLP - MCMF group develops an original process for confined nucleation and growth of molecular nanocrystals in silicate sol-gel matrices. This allows to prepare, through simple and generic one-step processes, bulk hybrid organic-inorganic nanocomposites and corresponding thin films and nanoparticles, for the development of highly sensitive fluorescent biosensors, filters or tracers for medical imaging. [bleu marine]Nanocrystals Ø = 60-80 nm emerging from silicate films after controlled surface dissolution. CNRS Patent PCT/FR2008/050490[/bleu marine]

Inorganic nanocrystals, oxides and borates, are also prepared by the sol-gel and polymeric precursor (modified Pechini) methods for the development of new fluorophores for lighting or ceramics for optics (MatONLP - MCMF and Supraconducteurs - MCBT).

[bleu marine] Inorganic nanopowders for lighting (white luminescence [/bleu marine]

Several chimie douce reactions are also investigated in lamellar cobaltates (SPMCE - MCMF) :
  • oxidative sodium extraction in aqueous solution
  • ion exchange Na <=> Ag in low-temperature molten salt
  • water intercalation giving rise to superconductivity

    [bleu marine]Chimie douce reaction schemes in lamellar cobaltates[/bleu marine]

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