*2.3.1. Nanoparticles*

For a research three different types of silver nanoparticles were used: silver nanoparticles of known dimensions (Ames Goldsmith Inc.), commercial form RucoBac AGP (Rudolph Chemie) and laboratory synthesized colloidal silver nanoparticles. Silver nanoparticles of known dimensions was medium density mono-dispersed 30 nm silver powder (Silver Nano Powder NP-30) and high density mono-dispersed 80 nm silver powder (Silver Nano Powder NP-80) [68]. The powdered silver nanoparticles are namely intended for a fine line printing (Ink-jet printing) and for electronics use. Because of their purity and known size they are very suitable and important for studies of adhesion to textile materials [69]. The initial con‐ centration of silver powders in the dyeing baths was 20 mg/l. Commercial form of silver nanoparticles RucoBac AGP is a hygienic finish for all fiber types. It is a highly concentrated hygiene and freshness system complying with the Oeko-Tex® standard 100. RucoBac AGP is a nano-dispersion of titanium dioxide (TiO2) as the carrier of the active component silver chloride (AgCl) [70]. The recommended concentration of RucoBac AGP is 0.2–0.5%. Labora‐ tory synthesized colloidal silver nanoparticles were made by a reduction of silver salt in an aqueous solution at room temperature. An amount of 25.5 mg of AgNO3 was dissolved in 750 ml of bi-distilled water, and argon gas was introduced into the solution for 30 min. The reduction was performed with 375 mg of NaBH4 under constant stirring. The solution was kept under an argon atmosphere for another hour [71].

#### *2.3.2. Dyeing of cotton samples*

#### *2.3.2.1. Dyeing with reactive dyes.*

Exhaust dyeing with or without the addition of silver nanoparticles [3, 27, 72] was per‐ formed on untreated and plasma-treated cotton samples. The dye solutions were separate‐ ly prepared using two different dyeing concentrations: blank (dyeing without dyestuff) and 0.05% on weight of fabric (owf) of Cibacron Deep Red S-B in liquor ratio 20 : 1. Dye‐ ing baths contained 30 g/l of salt (Na2SO4 anhydrous) and 8 g/l of sodium carbonate (Na2CO3 anhydrous). After the dyeing process, rinsing with distilled water was per‐ formed and neutralization with 1 ml/l of 30% acetic acid (CH3COOH). As a soaping agent 1 g/l of CIBAPON R was used.
