280 Tekstilec, 2018, 61(4), 280-288 DOI: 10.14502/Tekstilec2018.61.280-288 Corresponding author/Korespondenčna avtorica: Assist Prof dr. Marija Gorjanc E-mail: marija.gorjanc@ntf.uni-lj.si Anja Verbič 1 , Martin Šala 2 , Marija Gorjanc 1 1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Aškerčeva 12, SI-1000 Ljubljana, Slovenia 2 National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia The Infuence of in situ Synthesis Parameters on the Formation of ZnO Nanoparticles and the UPF Value of Cotton Fabric Vpliv parametrov sinteze in-situ na tvorbo nanodelcev ZnO in vrednost UZF bombažne tkanine Original Scientifc Article/Izvirni znanstveni članek Received/Prispelo 10-2018 • Accepted/Sprejeto 11-2018 Abstract The aim of this research was to investigate different parameters of the in situ synthesis of ZnO nanoparti- cles on cotton in order to achieve a high ultraviolet protection factor (UPF). In the first part of the research the influence of different reducing agents (Na 2 CO 3 , KOH, and NaOH) and their molar concentrations (0.1 M and 1 M) on the formation of ZnO nanoparticles and on the UPF values of cotton fabric were studied. The second part of the research was focused on the other parameters of in situ synthesis, such as the syn- thesis time ratio (time ratio between the treatment of the fabric in the precursor (ZnCl 2 ) and treatment af- ter the reducing agent was added) and drying period duration after the in situ synthesis. Using UV/Vis spec- troscopy, high UPF values (UPF 50+) were measured for cotton fabrics where in situ synthesis was performed using NaOH and KOH, both at 1 M molar concentration. Inductively coupled plasma mass spectrometry (ICP-MS) revealed a higher content of zinc on the fabric when NaOH was used. Scanning electron micros- copy (SEM) showed that use of this reducing agent resulted in cotton fabric completely covered with small, round shaped nanoparticles. From the second part of the research, it was found that longer treatment times after the reducing agent was added produced functionalised cotton fabric with higher UPF values. The dry- ing period duration after in situ synthesis did not significantly affect the UPF value of the fabric, but it did influence the morphology of the synthesised nanoparticles. With a longer drying time the nanoparticles were more rounded. The samples had poor wash fastness even after the first wash, which was found through low UPF values. Keywords: in situ synthesis, nanoparticles, zinc oxide, UV radiation, cotton, UV protection Izvleček Namen raziskave je bil proučiti pogoje in situ sinteze nanodelcev cinkovega oksida na bombažni tkanini in doseči visok ultravijolični zaščitni faktor (UZF) funkcionalizirane tkanine. V prvem delu raziskave je bil pro- učevan vpliv vrste reducentov (Na 2 CO 3 , KOH, NaOH) in njihove molarne koncentracije (0,1M in 1M) na obli- kovanje nanodelcev ZnO na bombažni tkanini. V drugem delu raziskave so bili proučevani še drugi dejavni- ki, kot so časovno razmerje sinteze (razmerje med časom obdelave tkanine v prekurzorju in obdelave po dodatku reducenta) in čas sušenja po sintezi in situ. Visoke vrednosti UZF (50+), ki so bile določene na UV/ Vis- spektrofotometru, so bile dosežene pri sintezi in situ ZnO-ND z uporabo NaOH in KOH v molarni koncen- traciji 1M. Masna-spektrometrična analiza induktivno sklopljene plazme (ICP-MS) je potrdila večjo vsebnost cinka na tkanini, kjer je bil za sintezo in situ uporabljen NaOH. Iz posnetkov vrstične elektronske mikroskopi- je (SEM) je bilo razvidno, da so bili z uporabo NaOH pri sintezi in situ oblikovani ZnO nanodelci okrogle oblike,