Tailoring of multifunctional cotton fabric by embedding a TiO2+ZnO composite into a chitosan matrix

The use of nanomaterials to functionalise textiles offers new opportunities for chemical modification of textile fibres’ surfaces to achieve multifunctional protective properties. In this study, novel coatings were tailored on cotton fabric by embedding a mixture of TiO2 and ZnO nanoparticles (NPs) of different molar ratios into a chitosan polymer matrix. The excitation energies of the TiO2+ZnO composites generated in the coatings ranged from 3.20 eV to 3.25 eV, indicating that the photocatalytic performance of the functionalised cotton was driven by UV light. The presence of TiO2+ZnO composites increased the UV protection factor (UPF) of the cotton fabric from 4.2 for the untreated sample to 15–21 for the functionalised samples. The UPF values of the coatings slightly decreased after repeated washing. The ZnO in the TiO2+ZnO composites conferred biocidal activity to the coatings, which were resistant to washing at higher ZnO concentrations. In addition, the TiO2 in the TiO2+ZnO composites was responsible for the enhanced photocatalytic self-cleaning of the functionalised cotton, which was observed during the initial period of illumination at lower ZnO concentrations in the composite. The main advantage of these TiO2+ZnO composite coatings is their multifunctionality, which cannot be provided by single-component TiO2 or ZnO coatings. Moreover, these coatings have wide-ranging practical applications, as they were composed of commercially available nanomaterials and were applied using conventional pad–dry–cure equipment.