Abstract
Cotton garments were coated with titanium dioxide particles consisting of small single crystals. Organic soils such as liquid paraffin, triolein and oleic acid were used as organic dirt coming from human skin. The fabric with titanium dioxide was immersed into aceton solutions of these compounds, withdrawn, and then irradiated with UV with a low pressure Hg lamp. Detergency was calculated from spectral reflectance before and after UV irradiation. In case of liquid paraffin, positive detergency values were obtained in regions with wavelengths of 400 nm or above, but negative ones were obtained in regions with wavelengths of less than 300 nm. On the other hand, positive detergency values were observed in wavelengths of 600 nm or above; however, in regions with wavelengths of less than 400 nm, negative ones were observed for soils such as triolein and oleic acid. A positive value of detergency means that the soil was removed by decomposition from the cotton surface by the titanium dioxide photo-catalytic action. For negative values of detergency, it may be considered that coloration due to changes in chemical structure of soils.
