Achieving Nano-Scale Surface Structure on Wool Fabric by Atmospheric Pressure Plasma Treatment

Atmospheric pressure plasma (APP) treatment is attracting increasing attention in industrial applications as it is potentially capable of continuous surface modification of a substrate. A comprehensive study of surface morphology and surface chemistry of wool fibres after plasma treatment with varying operational parameters (treatment time, ignition power, oxygen concentration, and jet distance) was conducted with helium and oxygen gas as carrier and reactive gas, respectively. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used for characterising the plasma-treated wool. APP could produce crystalline structures on wool cuticles which assist wicking and spreading of liquids. A complete wetting of wool fabric was observed after exposure to the plasma for a very short period. Experimental results revealed that the change in the wetting behaviour was caused by surface oxidation and cleavage of disulphide crosslinks of wool cuticles. APP treatment was found to be effective in achieving hydrophilisation of hydrophobic wool fibres. In addition, nano-scale surface modification was observed and thus improved hydrophilicity of wool fabric was achieved. The nano-scale surface structure was obtained with proper control of plasma treatment operational parameters. This study provides essential guidelines for manipulation of parameters for achieving nano-scale surface modification and desirable surface properties of wool fibres using plasma technology.