The diploma thesis investigated the in situ synthesis of silver nanoparticles (Ag NPs) within a chitosan matrix on viscose fabric using kombucha, as an eco-friendly reducing and stabilising agent. The chitosan matrix was crosslinked with 1,2,3,4-butanetetracarboxylic acid (BTCA) by two procedures: in the single-bath procedure (P1), chitosan and BTCA were applied from a common impregnation bath, while in the two-step procedure (P2), BTCA was applied first and chitosan subsequently. The synthesis of Ag NPs was carried out for two hours at 35 °C in partially neutralised kombucha with the addition of a 2 mM AgNO3 solution. The analyses of morphological, chemical and optical properties confirmed the successful in situ synthesis of Ag NPs, while the mode of chitosan crosslinking markedly influenced their distribution and properties. Procedure P1 provided a more uniform distribution of Ag NPs along the fibres and a more pronounced localised surface plasmon resonance (LSPR) peak at approximately 420 nm, whereas procedure P2 resulted in larger local deposits and agglomerates. Both functionalized samples exhibited complete inhibition of the growth of Escherichia coli and Staphylococcus aureus before and after one and five laundering cycles. Following ten laundering cycles, the antibacterial activity decreased; nevertheless, the sample treated according to P1 still demonstrated satisfactory antibacterial performance. Functionalization slightly improved the UV-protective properties of the viscose fabric and increased its bending rigidity without reducing its air permeability. Consistent with the increased stiffness, both functionalized samples exhibited lower elongation at break. In addition, procedure P1 resulted in a slight reduction in tensile strength, whereas procedure P2 led to its increase, indicating more efficient transfer of tensile loads through the textile structure. The results confirm that the crosslinking strategy of the chitosan matrix is a key factor governing the microstructure of the functional coating, which determines the distribution of Ag NPs and, consequently, the optical, UV-protective, antibacterial, and physico-mechanical properties of the functionalized textile. This study presents a sustainable approach for the preparation of multifunctional textiles by employing natural reducing agents while minimizing the use of synthetic chemicals.
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