3.1.4. Self-Cleaning of Blank and SiO2-NP–Cotton/Lycra Composite Fabrics

Table 5 showed that the K/S values of SiO2NP/cotton/lycra composite fabrics exposed to sunlight decreased compared to blank fabrics. Compared to the untreated samples, the results of both SiO2-NP/cotton/lycra (94.5/5.5%) fabric of 19 pick/cm and cotton/lycra (90.8/9.2%) fabric of 19 pick/cm samples demonstrated greater self-cleaning activity, attributable to the fact that transition metal oxides and their composites, such as SiO2 NPs, have strong photocatalytic activity for the photodegradation of organic pollutants, as illustrated in Figure 7. Metal oxide-based nanomaterials with well-controlled structural, crystalline, and surface characteristics behave as semiconductors with broadband gaps and have desirable attributes, including non-toxicity and stability.

**Figure 7.** Self-cleaning of the blank and SiO2NP/cotton/lycra composite fabrics before and after light exposure.


**Table 5.** Self-cleaning of the blank and SiO2-NP/cotton/lycra composite fabrics.

Note. K/S = (Color strength).

### **4. Conclusions**

This research demonstrated the effect of both adding lycra yarns with different densities and implementation of SiO2 NPs on the functional properties of plain pile cotton fabrics to produce composites. The SiO2 NP coated cotton/lycra composites showed significant self-cleaning activity with 24 h of exposure. The self-cleaning results are identical in both the cotton/lycra (94.5/5.5%) and cotton/lycra (90.8/9.2%) 19 pick/cm samples (96.9 and 96.5 values), respectively. Besides the intrinsic antibacterial properties, the inclusion of SiO2 NPs will simultaneously lead to the effective antibacterial activity of the fabricated surface. The pile density of 19 pick/cm provides higher bactericidal activity (30–31 mm) compared to other densities. The composite positively influenced the UV protection characteristics compared to blank samples. However, cotton/lycra (90.8/9.2%) 19 pick/cm sample showed higher UPF (4676.8) than did cotton/lycra (94.5/5.5%) 19 pick/cm sample (2690.4). In summary, the cotton/lycra (90.5/9.2%) 19 pick/cm sample showed the best results in terms of antibacterial activity, UV protection, and self-cleaning.

**Author Contributions:** Conceptualization, T.A.E. and G.M.E.; methodology, H.G.E.; software, G.M.E. validation, H.G.E., H.H.E. and T.A.E.; formal analysis, K.S.-A.; investigation, H.G.E.; resources, H.G.E.; data curation, H.G.E.; writing—original draft preparation, H.G.E.; writing—review and editing, T.A.E. and M.R.P.; visualization, M.R.P.; supervision, T.A.E.; project administration, T.A.E. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.

**Conflicts of Interest:** The authors declare no conflict of interest.
