The development of nanocomposites combining photocatalytic, antifouling and
protective features has provided interesting and promising results in the last years. However, few data about the behaviour
of the nanomaterials applied on stone surfaces are available in the literature. In the framework of the EU-Horizon 2020 project
“Nano-Cathedral”, nanostructured protective treatments have been designed with different nanoparticles (TiO2, Ag, ZnO), solvents
and silane/siloxane-based polymeric matrices. The innovative formulations have been applied on 6 lithotypes, selected among
the stones used in five medieval cathedrals (Vitoria-Gasteiz, Ghent, Cologne, Vienna and Pisa) and a contemporary theatre
(Oslo Opera House), which are emblematic of different European geological and environmental areas. The treated stone specimens
have been fully characterized to evaluate the surface optical and morphological compatibility, the reduction of water absorption
by capillarity, the change in wettability and
water vapour permeability properties. The selected treatments fulfil all these requirements and exhibit good photocatalytic
and antifouling properties once applied on stone specimens.
Different accelerated ageing procedures have also been performed in order to evaluate the stability of the polymeric matrices
in the presence of photoactive TiO2.
Johannes Weber, M Roveri, F Gherardi, S Goidanich, D Gulotta, V Castelvetro, R Fischer, L Winandy, L Toniolo