Structure and surface coverage of water-based stearate coatings on calcium carbonate nanoparticles

Xuetao Shi, I. Bertóti, B. Pukánszky, Roberto Rosa, Andrea Lazzeri

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

In a preceding paper it was found that, during coating with solutions of a stearin salt in water, whatever the concentration used, a considerable part of the PCC surface remains free, indicating the development of an incomplete monolayer. This was explained by assuming a micelle adsorption mechanism as the dominating process in water, resulting in the formation of a multilayer structure composed of an inner incomplete chemisorbed monolayer and one or more physically adsorbed layers. This model predicted a physisorbed layer in which polar groups are oriented outwards of the particles, resulting in a hydrophilic surface, and contrary to experimental evidence. In this paper we propose that during the drying stage the physisorbed calcium stearate layers undergo a complex rearrangement leading to a hydrophobic coating with the aliphatic tails oriented outwards of the particles. The results of XRD measurements proved that the physisorbed stearate layer is crystalline, while DSC model experiments indicated that the layer goes through phase transitions during heat treatment. The proposed model matched with IGC measurements, showing a clear dependence of the specific component of surface energy on the amount of absorbed stearin. The agreement with values obtained for solvent and dry-coated particles support the proposed rearrangement of alkanoate molecules in the coating.

Original languageEnglish
Pages (from-to)67-73
Number of pages7
JournalJournal of Colloid and Interface Science
Volume362
Issue number1
DOIs
Publication statusPublished - Oct 1 2011

Fingerprint

Stearates
Calcium Carbonate
Calcium carbonate
Nanoparticles
Coatings
Water
Monolayers
Calcium stearate
Micelles
Interfacial energy
Drying
Multilayers
Salts
Phase transitions
Heat treatment
Crystalline materials
Adsorption
Molecules
Experiments

Keywords

  • Micelle adsorption mechanism
  • Monolayer coverage
  • Precipitated calcium carbonate
  • Stearin
  • Surface energy
  • Water coating

ASJC Scopus subject areas

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

Cite this

Structure and surface coverage of water-based stearate coatings on calcium carbonate nanoparticles. / Shi, Xuetao; Bertóti, I.; Pukánszky, B.; Rosa, Roberto; Lazzeri, Andrea.

In: Journal of Colloid and Interface Science, Vol. 362, No. 1, 01.10.2011, p. 67-73.

Research output: Contribution to journalArticle

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