Wettability and photodegradation activity of sol-gel dip-coated zinc oxide films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The hydrophilic characteristics of zinc oxide combined with the electronic properties of this width band gap semi-conductor were used to produce transparent, anti fog and photocatalytic porous films by using a simple sol-gel dip-coating process. The observed values of contact angles (near to 10A degrees) and calculated spreading coefficients (close to zero) indicate that sol-gel dip-coated ZnO porous films show excellent wettability. The photocatalytic behavior of these films measured from methylene blue degradation is dependent on the film thickness in agreement with wettability results; as the film thickness increases from 0.1 +/- A 0.05 to 0.5 +/- A 0.05 the photocatalytic reaction rate constant increases from 0.9 x 10(-3) to 5.5 x 10(-3) min(-1).