title: Single step hybrid coating process to enhance the electrosteric stabilization of inorganic particles.
abstract: We report on a single-step coating process and the resulting colloidal stability of silica-coated spindle-type hematite nanoparticles (NPs) decorated with a layer of poly(acrylic acid) (PAA) polyelectrolyte chains that are partially incorporated into the silica shell. The stability of PAA coated NPs as a function of pH and salt concentration in water was compared to bare hematite particles and simple silica-coated hematite NPs, studying their electrophoretic mobility and the hydrodynamic radius by dynamic light scattering. Particles coated with this method were found to be more stable upon the addition of salt at pH 7, and their aggregation at the pH of the isoelectric point is reversible. The hybrid coating appears to increase the colloidal stability in aqueous media due to the combination of the decrease of the isoelectric point and the electrosteric stabilization. This coating method is not limited to hematite particles but can easily be adapted to any silica-coatable particle.
authors.affiliation: Adolphe Merkle Institute and Fribourg Center for Nanomaterials, University of Fribourg, Route de l'Ancienne Papeterie P.O. Box 209, 1723 Marly 1, Switzerland.
authors.forename: Chantal
authors.initials: C
authors.lastname: Rufier
authors.forename: Mathias
authors.initials: M
authors.lastname: Reufer
authors.forename: Hervé
authors.initials: H
authors.lastname: Dietsch
authors.forename: Peter
authors.initials: P
authors.lastname: Schurtenberger
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D057446:Hydrodynamics; D007202:Indicators and Reagents / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D005290:Ferric Compounds; D007202:Indicators and Reagents; D017640:Silicates; D014867:Water; C000499:ferric oxide; C006903:carbopol 940; D012822:Silicon Dioxide