Journal of Colloid and Interface Science, Vol.374, 61-69, 2012
Production of CaCO3/hyperbranched polyglycidol hybrid films using spray-coating technique
Biomineralizing organisms employ macromolecules and cellular processing strategies in order to produce highly complex composite materials such as nacre. Bionic approaches translating this knowledge into viable technical production schemes for a large-scale production of biomimetic hybrid materials have met with limited success so far. Investigations presented here thus focus on the production of CaCO3/polymer hybrid coatings that can be applied to huge surface areas via reactive spray-coating. Technical requirements for simplicity and cost efficiency include a straightforward one-pot synthesis of low molecular weight hyperbranched polyglycidols (polyethers of 2,3-epoxy-1-propanol) as a simple mimic of biological macromolecules. Polymers functionalized with phosphate monoester, sulfate or carboxylate groups provide a means of controlling CaCO3 particle density and morphology in the final coatings. We employ reactive spray-coating technique to generate CaCO3/hybrid coatings among which vaterite composites can be prepared in the presence of sulfate-containing hyperbranched polyglycidol. These coatings show high stability and remained unchanged for periods longer than 9 months. By employing carboxylate-based hyperbranched polyglycidol, it is possible to deposit vaterite-calcite composites, whereas phosphate-monoester-based hyperbranched polyglycidol leads to calcite composites. Nanoindentation was used to study mechanical properties, showing that coatings thus obtained are slightly harder than pure calcite. (C) 2012 Elsevier Inc. All rights reserved.
Keywords:Spray coating;Calcium carbonate composites;Vaterite;Functionalization of polymers;Hyperbranched polyglycidol