title: Multilayer films made from poly(allylamine) and phosphorous containing polyoxometalates: focus on the zeta potential.
abstract: The physicochemical characterization of coatings deposited in a step-by-step (SBS) manner relies most often on thickness and homogeneity measurements by means of atomic force microscopy. In the case of coatings produced from oppositely charged species, their surface potential, estimated through their zeta potential, was for a long time expected to change alternatively as a prerequisite for the film deposition. However, some counterexamples appeared in the literature where the growth of the coating was observed when the number of deposition steps was increased but without a regular change in the sign of the surface potential. These data showed that the interpretation of the zeta potential of SBS deposited films should be subjected to more attention. In this article, we show the occurrence of ionic strength dependent instability of the surface potential of films made from the alternated deposition of poly(allylamine hydrochloride) and polyoxoanions. This instability may be due to a structural change in the coating, but we cannot exclude some shear induced desorption during the zeta potential measurement. In addition, a change in ionic strength between the deposition of the coating and the measurement of its streaming potential can have a huge importance on the result.
authors.affiliation: Université de Strasbourg, Faculté de Chirurgie Dentaire, 1 place de l'Hôpital, 67000 Strasbourg, France; Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1121, 11 rue Humann, 67085 Strasbourg Cedex, France; Institut de Médecine Translationelle de Strasbourg, 1 place de l'Hôpital, 67000 Strasbourg, France. Electronic address: vball@unistra.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Ball
authors.forename: Christian
authors.initials: C
authors.lastname: Ringwald
authors.forename: Jérôme
authors.initials: J
authors.lastname: Bour
authors.forename: Marc
authors.initials: M
authors.lastname: Michel
authors.forename: Rami
authors.initials: R
authors.lastname: Al-Oweini
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kortz
mesh_terms: D008958:Models, Molecular; D009994:Osmolar Concentration; D010758:Phosphorus / Q000737:chemistry*; D011073:Polyamines / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D010758:Phosphorus; D011073:Polyamines; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates; C063994:polyallylamine
keywords: Layer-by-layer deposition; Polyoxometalate; Streaming potential; Zeta potential