Color shading, color fastness, antibacterial and ultraviolet protection properties of silk fabric colored by silver nanoparticles

This research studied the effects of different factors used in an in-situ method for forming colored silver nanoparticles (AgNP) on the properties of silk fabric; namely color shading, color strength, relative unlevelness index, color fastness to washing, antibacterial and UV shielding properties. In addition, improvement with an acrylic binder on color fastness to washing and antibacterial property after 20 cycles of washing of AgNP-treated silk fabric were also investigated. It was found that the optimum condition for treatment by the in-situ method was 2.0% owf of silver nitrate (AgNO3) solution, AgNO3 to trisodium citrate ratio at 1:3 (%w/w), exhaustion temperature at 90°C and treatment time at 90 or 120 min at pH 4.0. The higher concentration of those two factors, the higher the dark brown shade on the AgNP-treated silk fabrics. AgNP-treated silk fabric had a better UV protection than that of the pristine silk fabric. After 20 washes, the color fastness to washing of AgNP-treated silk fabric either with or without acrylic binder coating was rated low. Antibacterial activity against S. aureus of AgNP-treated silk fabric without coating acrylic binder decreased to 40% of bacterial reduction, but AgNP-treated silk fabric coated with acrylic binder still had 100% antibacterial property.