title: Nonuniform Growth of Composite Layer-by-Layer Assembled Coatings via Three-Dimensional Expansion of Hydrophobic Magnetite Nanoparticles.
abstract: Nanocomposite coatings are promising for a range of practical applications, and layer-by-layer assembly (LbL) is a versatile tool for nanocomposite formation. However, conventional LbL is a quite laborious procedure taking a lot of time to reach a sufficient thickness of the coatings required for practical applications. Herein, we proposed a novel variant of the LbL approach based on the deposition of hydrophilic polyelectrolyte molecules from a polar solvent and hydrophobic magnetite nanoparticles (NPs) from a nonpolar dispersion medium with an intermediate washing in the same polar solvent. The composite multilayers formed in this way exhibit exponential growth of the thickness and mass. On the basis of quartz crystal microbalance (QCM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and surface profile measurements, we propose a model describing the driving force of multilayer formation and the factors leading to nonlinear growth of their mass and thickness. The results allow one to expand the understanding of the mechanism of the LbL assembly in order to form multifunctional nanocomposites in a more efficient way.
authors.affiliation: Department of Nano- and Biomedical Technologies, Saratov State University , Saratov 410012, Russia.
authors.forename: Denis V
authors.initials: DV
authors.lastname: Voronin
authors.affiliation: Department of Interfaces, Max-Planck Institute of Colloids and Interfaces , Potsdam D14476, Germany.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Grigoriev
authors.affiliation: Department of Interfaces, Max-Planck Institute of Colloids and Interfaces , Potsdam D14476, Germany.
authors.forename: Helmuth
authors.initials: H
authors.lastname: Möhwald
authors.affiliation: Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom.
authors.forename: Dmitry G
authors.initials: DG
authors.lastname: Shchukin
authors.affiliation: Department of Nano- and Biomedical Technologies, Saratov State University , Saratov 410012, Russia.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Gorin
keywords: exponential growth; hydrophobic interactions; magnetic nanocomposites; polyelectrolytes; surface hydrophobization