Influence of counter-ions on antifogging coatings

Abstract

The influence of different counter-ions on the superhydrophilic and antifogging behavior of polyelectrolyte multilayers was examined. Multilayers assembled with a polymer anion and amine-modified silica nanoparticles were treated with salt solutions of monovalent and divalent cations. Refraction index of the films dropped significantly when treated with monovalent cations, and increased when treated with divalent cations. It has been found that the refraction index decrease in films treated with monovalent salts may be correlated with porosity increase in treated films, and this porosity increase in turn linked with an increase in hydrophilicity. Polyelectrolyte films have yet to show long-lasting antifogging properties on the commercially valuable polycarbonate, but monovalent cations may have improved the longevity of antifogging properties of the multilayer on polycarbonate, and warrant further study.