**9. Self-Cleaning of Untreatedand Treated Polyester Fabrics with ZnO or TiO2 NPs**

One of the benefits of polyester fabrics coated with nanoparticles is the conversion of absorbed light into self-cleaning substances to remove stains. To gain the self-cleaning properties of nano ZnO or TiO2 particles, the photodegradation of methyl red and methylene blue adsorbed on nano ZnO or TiO2 treated polyester fabrics was explored (Table 7).


**Table 7.** Effect of Light fastness and Stains \* on ZnO or TiO2 NPs treated polyester fabrics.

\* Photo-stimulated color removal on polyester: 60 μL methyl red or methylene blue was marked on both posttreated ZnO or TiO2 nanoparticles (0.5–2.5% w.o.ffor ZnO and 1–5% w.o.f for TiO2)-treated polyester and the untreated fabrics. The polyester fabrics were illuminated through exposure to an ultraviolet lamp for 24 h for ZnO and 12 h forTiO2.

After 24 and 12 h of UV exposure, Table 7 displays the results of methyl red and methylene blue stains on polyester fabrics treated with ZnO or TiO2 NPs. For polyester fabrics treated with ZnO or TiO2 NPs, a partial discoloration of methyl red and methylene blue stains brought on by ultraviolet radiation was seen. When polyester fabric is treated with ZnO or TiO2 NPs, thin layers of ZnO or TiO2 nanoparticles develop, increasing the fabric's hydrophobic qualities. A hydrophobic surface stops dirt from adhering, keeping the polyester surface clean at all times. The results showed that the highest rates of photodegradation on the surface were 60–70% for methyl red stains treated with ZnO NPs after 24 h and 60–80% after 12 h for methylene blue stains treated with TiO2 NPs (Table 7).
