Cementitious Composite Materials for Self-Sterilization Surfaces

This paper studies the antibacterial activity of different TiO2 nano-
structures (fine-particulate TiO2, TiO2-anatase, and TiO2-rutile) for
self-sterilization applications. It is divided into three parts. The first
part deals with the investigation of radical production by means
of the p-nitrosodimethylaniline (RNO)-bleaching method. In the
second part, the effect of incorporating TiO2 into a cement-based
composite on its microstructure is evaluated. In the third part, the
antibacterial performance is assessed. The results demonstrated
that fine-particulate TiO2 has the highest rate of hydroxyl radical
production (2.5 times higher than that of TiO2-anatase) owing to
its high specific surface area. TiO2 nanoparticles tend to agglom-
erate/aggregate during the mixing process, reducing the surface
area available for the photocatalytic process. However, fine-
particulate TiO2 agglomeration can be suppressed under strong
alkaline conditions. A significant antibacterial effect was achieved
by the sample with fine-particulate TiO2. The percentage of the
infected area is less than 5% for the cement sample containing 5%
of fine-particulate TiO2, while the control specimen has more than
15% of the infected area.