Structural, optical, and adsorption properties of ZnO2/poly(acrylic acid) hybrid thin porous films prepared by ionic strength controlled layer-by-layer method

Edit Pál, Dániel Sebok, Viktória Hornok, Imre Dékány

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

ZnO2/poly(acrylic acid) sandwich structures were prepared by layer-by-layer (LbL) self-assembly. The structure and optical behavior of the hybrid films were controlled by changing the surface charge and conformation of the poly(acrylic acid). The buildup of the films was followed by UV-vis absorption and reflection spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD), and quartz crystal microbalance (QCM) measurements. It was found that the ionic strength of the polymer solution had a great influence on the film thickness which, in turn, affected the optical properties. The water vapor adsorption isotherms of the films determined by QCM showed an adsorption hysteresis characteristic of porous thin layer structures. The adsorption of water molecules inside the films changed the effective refractive index resulting in a change of the reflection properties. This phenomenon is shown to be exploited for the application of the films as optical sensors. The polarizability of water molecules in the adsorption layer was also determined. It was found that polarization of water molecules in the adsorption layer is much lower than in the liquid water when the surface coverage (Θ) is low.

Original languageEnglish
Pages (from-to)173-182
Number of pages10
JournalJournal of colloid and interface science
Volume332
Issue number1
DOIs
Publication statusPublished - Apr 1 2009

Keywords

  • Layer-by-layer
  • Optical sensor
  • Polyelectrolyte
  • QCM
  • Thin layer
  • Vapor adsorption
  • ZnO

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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