Free radical formation in wool fibers treated by low temperature plasma

Abstract

Electron spin resonance studies of merino wool fabrics provide evidence of the presence of stable free radicals. Ultraviolet/visible (λ > 250 nm) irradiation increases the radical concentration. Nitrogen, air, and water vapor plasma treatments on wool fabrics result in new signal bands attributed to nitrogen-centered radicals. The formation of the different additional radicals could be related to the high reactivity of the plasma species or to the vacuum-ultraviolet radiation component (λ < 200 nm) of the plasma environment. The presence of these radicals depends on the treatment time and the kind of gas used for plasma generation.