Namen diplomske naloge je preučiti vpliv kemičnih vlaken v bombažnih in volnenih vzorcih na potencial zeta. Vzorci, ki smo jih dobili iz dveh tekstilnih podjetij Beti preja d.o.o. in Galeb d.d. so bili različnih sestav bombaž/modakril in volna/viskoza/poliamid. Potencial zeta je parameter, ki odraža medfazne lastnosti in je zelo pomemben za razumevanje vedenja trdnih snovi v številnih tehničnih postopkih. To daje vpogled v naboj in adsorpcijske lastnosti trdnih površin. Potencial zeta opisuje elektrokinetične lastnosti na meji trdno/tekoče, kjer pride do interakcij med trdno in tekočo fazo. Ta medfazna površina je opisana s kemičnim in elektrokemičnim potencialom, ki je popolnoma drugačen, kot tisti v čisti tekoči oz. trdni fazi, saj na molekule na meji vplivajo interakcijske sile iz obeh prisotnih faz. Za določitev potenciala zeta smo uporabili elektrokinetični analizator SurPASS proizvajalca Anton Paar GmbH iz Gradca v Avstriji, ki nam s pomočjo programske opreme »Visiolab for SurPAS« izračuna potencial zeta iz merjenega pretočnega potenciala. Za merjenje potenciala zeta smo uporabili cilindrično celico za vzorce prej in pravokotno merilno celico z nastavljivo režo za merjenje pletenin. Merili smo pretočni potencial za določitev potenciala zeta vzorcem sestave bombaž/modakril in volna/viskoza/poliamid. Iz dobljenih podatkov potenciala zeta v odvisnosti od pH vrednosti smo ovrednotili podatke in preučili vpliv kemičnih vlaken na potencial zeta. The intention of diploma work was to study the influence of chemical fibres on zeta potential in regard to cotton and woollen samples. These samples were obtained from two textile companies, Beti preja d.o.o. and Galeb d.d., and contained different compositions cotton/modacryl and wool/viscose/polyamide, respectively. Zeta potential is a parameter that reflects the characteristics of solid/liquid interfaces, and is very important for understanding the behaviours of solids within several technical processes. This provides an insight into the charge and adsorption properties of a solid’s surfaces. Zeta potential describes those electro-kinetic properties on the borders of a solid/liquid, where interaction takes place between the solid and liquid phases. This interface is described by chemical and electrochemical potential, which is completely different to that in bulk liquid or solid phases, since the molecules on the borders affect the interaction forces from both phases. The electro-kinetic analyzer SurPASS produced by Anton Paar GmbH from Graz, Austria was used to calculate the zeta potential. With the help of »Visiolab for SurPASS«, the software of SurPASS, the zeta potential was calculated from the measured streaming potential and streaming current. Two measuring cells were used for measuring the zeta potential. Cylindrical cell was used for measuring the yarn samples and adjustable gap cell for measuring the knitwear. The measurements were based on modelled structure of cotton/modacrylic and wool/viscose/polyamide. From the data obtained, zeta potential versus pH data was evaluated, and impacts of chemical fibres on the zeta potential were examined.