Photocatalytic and antimicrobial effects of interior paints

The interior paints investigated have been formulated on the basis of aqueous acrylic dispersion, rutile titanium dioxide, extenders and special additives as photocatalytic nano zinc oxide and different types of photocatalytic anatase titanium dioxide. Organic dye Orange 11 was used as an indicator for the reactivity of photocatalytic surfaces. The absorbance change of Orange 11 solution was measured by a photometer. An agar plate method was used for the evaluation of antimicrobial effect of the coatings. The effectiveness of coatings was demonstrated using the following bacteria relevant to hygiene: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, fungi Aspergillus niger and Penicillium chrysogenum. The nano-form of ZnO was found to be the best photocatalytic agent and also the best and broadest spectrum antimicrobial agent for these interior paints. Statistically significant differences between the control coatings and the coatings with nano-form of ZnO were found using Rank-sum test. (C) 2009 Elsevier B.V. All rights reserved.