This doctoral thesis presents an innovative and sustainable approach for the development of durable, multifunctional, nanocomposite protective coatings for textile applications involving the combination of TiO2 with a mixture of different organofunctional trialkoxysilane precursors. An optimized 4% titanium isopropoxide (TTIP) was used as TiO2 precursor. Using in-situ low temperature sol-gel and sol-gel/hydrothermal methods, TiO2 was loaded with Ag (Ag-TiO2) or coupled with reduced graphene oxide rGO (rGO/TiO2) and additionally modified with the biobarrier-forming [3-(trimethoxysilyl)propyl]ammonium chloride (SiQAC) or aminopropyltriethoxysilane (APTES) and the phosphorus-containing flame retardant (trihydroxysilyl)propylmethylphosphonate (TPMP). Ag-TiO2 combined the photocatalytic efficiency of TiO₂ with the controlled release of biocidal Ag/Ag₂O, providing an effective self-sterilizing surface, improved UV protection and photocatalytic self-cleaning activity. The functionalization with SiQAC or TPMP created a highly cross-linked organic-inorganic hybrid network through Si–O–Ti and Si–O–Si bonds, with the Si–O–C bonds interacting with cellulose functional groups. SiQAC impaired UV protection of Ag-TiO2 but formed an additional passive and active bio-barrier and facilitated the formation of the Ag/AgCl/TiO2 heterostructure, which improved the photocatalytic activity of Ag-TiO2. TPMP together with ROS and Ag0/Ag+ provided antibacterial activity as well as increased thermo-oxidative stability and flame retardancy without compromising UV blocking of-TiO2. Functionalization with a TPMP/SiQAC or TPMP/APTES mixtures affected the formation of Ag species after Ag loading of TiO2 and influenced the overall multifunctional performance through TiO2/Ag/AgCl or TiO2/Ag heterocomposites, with the TTIP/TPMP/SIQAC or TTIP/TPMP/APTES mixture being optimal in equimolar ratio. The introduction of rGO of higher concentration into the TPMP/APTES-functionalized TiO₂ system proved to be a more environmentally friendly alternative to functionalized Ag-TiO2, whereas the sol-gel route delivered superior multifunctional performance compared to sol-gel/hydrothermal method. Each of the novel nanocomposite coatings is a viable option for further sustainable development of technical textiles and offers different advantages for various specific applications.
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