Cellulose fibers modified with silver nanoparticles were prepared using N-methylmorpholine-N-oxide as a direct solvent and analyzed in this study. Silver nanoparticles were generated as a product of AgNO 3 reduction by means of three methods under varying light conditions (daylight and darkroom). Influence of generating conditions on the size, the type and the number weighting of created nanoparticles was examined. Dynamic Light Scattering technique (DLS) was used for determination of those parameters. DLS analysis showed that the best method, i.e. the one that allowed the generation of the greatest number of silver nanoparticles with the smallest diameter and the smallest agglomerates, was incubation of cellulose pulp with AgNO 3 in a darkroom for 24 h. Mechanical and hydrophilic properties of all obtained fibers were also determined. Results showed that the method of silver nanoparticles generation did not influence significantly mechanical and hydrophilic properties of the modified fibers, because in all cases only small decreases of the studied parameters were observed.

In the present research, nanocomposite antibacterial cellulose fibers of Lyocell type modified with nanosilver particles and nanosilica were obtained. Nanosilver particles were generated by the chemical reduction of silver nitrate (AgNO 3 ) in 50% water solution of N-methylmorpholine N-oxide (NMMO), which was applied as a direct cellulose solvent for the production of Lyocell fibers. The main aim of this study has been to obtain antibacterial cellulose fibers modified with silver nanoparticles, which are entirely safe for contact with human tissue. Taking into account the potential medical applications of the obtained fibers, the antibacterial activity and cytotoxicity of silver nanoparticles enclosed in fibers were examined in human and mouse cells. Considering the size of the silver nanoparticles with nanosilica in NMMO and their physical properties, the time of generation was the subject of a thorough analysis. The basic physical properties of the nanoparticles introduced in the fibers were tested using the UV/VIS, DLS and TEM methods. The basic properties of the fibers, namely the mechanical and hydrophilic ones, and the average degree of polymerisation of the cellulose fibers were estimated. The conditions of the synthesis of nanoparticles in NMMO with nanosilica were optimised. The results have confirmed that fibers with high-quality antibacterial properties, safe for human tissue and suitable for medical purposes, could be obtained.

The widespread demand for multifunctional materials that can be used for anticounterfeiting purposes, as dual-mode phosphors, or as optical nanothermometers has inspired us to synthesize Yb3+/Tm3+/Ln3+ (Ln = Eu, Tb)-doped LaPO4 nanoparticles (NPs) and, based on these, luminescent fibers that utilize and extend the properties of the NPs. They show intense dual-mode color-tunable emission and temperature-dependent up-conversion (UC) luminescence, which makes them multifunctional and of a high potential applicability. The nanomaterials were obtained by a simple and fast coprecipitation method, yielding pure-phase monoclinic products. The products were used as luminescence activators in cellulose fibers, showing their potential applications for security purposes. They can emit strong UC and down-conversion luminescence within one particle, under excitation of commercially available near-infrared (NIR) and ultraviolet (UV) excitation sources. The pure red and green emissions under UV irradiation resulted from the presence of Eu3+ or Tb3+ ions in the structure of the products, whereas violet-blue emission was obtained under NIR excitation because of Yb3+ and Tm3+ codopants. After simultaneous UV/NIR double-laser excitation, they obtained NPs that show a complex luminescence resulting from Tm3+ (after energy transfer from Yb3+), Tb3+, or Eu3+. The obtained UC emission can be tuned, giving a huge color shift (from orange or green to blue). What is more, thanks to the presence of thermalized levels of Tm3+ ions, these materials can act as promising temperature nanosensors in a wide range of temperatures from 293 to 679 K. Using the fluorescence intensity ratio technique, relatively high thermal sensitivity (S r) was obtained, 0.024 and 0.022 K–1 for 293 K for the Yb3+/Tm3+/Eu3+ and Yb3+/Tm3+/Tb3+ samples, respectively.

Silver nanoparticles were embedded into cellulose fibres using N‐methylmorpholine N‐oxide as a direct cellulose solvent that was also the system from which silver nanoparticles were generated. The process of generation of silver nanoparticles in the N‐methylmorpholine N‐oxide enables the properties of cellulose fibres to be modified without any additional reducing agent, which makes this process more environmentally friendly. By varying the reaction time of the precursor with the N‐methylmorpholine N‐oxide, a range of nanoparticle sizes was obtained. The fibres contain the same concentration of silver, but, on account of the varying morphology of the nanoparticles, they show a range of colour shades. The primary aim of this study was to show how temperature and reaction time affect the basic parameters of the obtained nanoparticles (shape, size, and distribution in the polymer matrix of fibres), which consequently influences the colour of the modified cellulose fibres. Nanoparticles were characterised by dynamic light scattering and transmission electron microscopy methods, while the fibre hues were estimated by colorimetric analysis. Trichromatic coordinates of colour x, y were delineated, and the colour was identified by positioning the x and y values in the CIE chromaticity diagram. It is noted that many parameters, especially the diameter and shape of the silver nanoparticles, influence the colour of the fibre obtained.