The aim of the research was to develop a smart viscose fabric with temperature and pH responsive properties and proactive antimicrobial protection. Poly-(N-isopropylakrylamide)/chitosan (PNCS) microgel was used as the carrier of silver nanoparticles (Ag NPs), which were synthesised by green biosynthesis using 1 and 5 mM solution of AgNO3 and sumac leaf extract. PNCS microgel and Ag NP were applied to the viscose fabric using a one-step and a two-step process. The one-step procedure involved the in situ synthesis of Ag NPs on the surface of viscose fibres previously modified with PNCS microgel and polysiloxane matrix. The two-step procedure, on the other hand, involved the direct immobilisation of Ag NPs by dehydration/hydration of the PNCS microgel with the nanodispersion of Ag NPs in sumac leaf extract and subsequent application to the polysiloxane matrix-coated viscose fibres. The results of morphological, chemical and functional properties of the modified samples showed that the PNCS microgel is a suitable carrier for biosynthesized Ag NPs on the surface of the viscose fibres, with a significant effect on the application process. Compared to the two-step process, the one-step process showed a higher concentration of Ag NPs on the fibres, which in combination with the phenolic components of the sumac leaf extract coloured the samples brown to brown-green and provided UV protection with a UPF value of 50+. The application procedure and concentration of Ag NPs slightly hindered the temperature response of the PNCS microgel. While increasing the Ag NPs concentration resulted in lower temperature sensitivity of the PNCS microgel, the application procedure affected the pH response, which was better maintained in the samples modified by the two-step process. In agreement with the higher concentration of Ag NPs, the samples modified by the two-step process showed excellent (more than 90%) reduction of the test bacteria E. coli and S. aureus. In this case, the PNCS microgel acted as a reservoir for Ag NPs, whose release was based on a diffusion-controlled mechanism due to the increased porosity of the PNCS microgel in the swollen phase.
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