title: Layer-by-layer deposition of tannic acid and Fe³⁺ cations is of electrostatic nature but almost ionic strength independent at pH 5.
abstract: The step-by-step assembly of tannic acid (TA) and of Fe(3+) cations allows to produce films of controlled thickness using exclusively small multivalent ions. In the present investigation, it is shown that even if electrostatic interactions are dominant over ligand to metal charge transfer interactions in stabilizing such films, those electrostatic interactions display a small sensitivity to concentration in NaCl used as a supporting electrolyte as well as to the concentration in sodium acetate in the absence of NaCl. This finding highlights the strong stability of the films obtained through the step-by-step deposition of TA and Fe(3+) cations. Complementarily, the films made from 6 deposition cycles of TA and Fe(3+) cations do not form Prussian Blue when put in contact with hexacyanoferrate anions. This shows that Fe(3+) is so tightly bound to the film that it is not able to form a coordination polymer with Fe(CN)6(4-) anions.
authors: Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1121, Faculté de Médecine, 11 rue Humann, 67085 Strasbourg Cedex, France.
authors: Christian
authors: C
authors: Ringwald
authors: Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1121, Faculté de Médecine, 11 rue Humann, 67085 Strasbourg Cedex, France; Faculté de Chirurgie Dentaire, 8 rue Sainte Elisabeth, 67000 Strasbourg, France. Electronic address: vball@unistra.fr.
authors: Vincent
authors: V
authors: Ball
mesh_terms: D002412:Cations / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D009994:Osmolar Concentration; D055672:Static Electricity; D013634:Tannins / Q000737:chemistry*
chemical_list: D002412:Cations; D013634:Tannins; D007501:Iron
keywords: Coordination driven self-assembly; Fe(3+) cations; Influence of the ionic strength; Tannic acid