Dyeing of plasma treated cotton and bamboo rayon with Fallopia japonica extract

To achieve colourful and antibacterial textiles using ecologically friendly processes, cotton and bamboo rayon knitted fabrics were treated using radio-frequency low-pressure water vapour plasma and dyed with the extract of Fallopia japonica (Japanese knotweed) rhizome. Optical emission spectroscopy (OES) was used to observe plasma during the sample treatment and scanning electron microscopy (SEM) to study morphological changes of samples. The adsorption of F. japonica on cellulose substrates was studied by measuring the colour (CIE L*a*b*) and colour yield (K/S) of dyed samples. The antibacterial properties against Escherichia coli and Staphylococcus aureus were tested as well. The results show that water vapour plasma induces weak etching effect on the surface of the cellulose samples, since water molecules in plasma dissociate to produce hydroxyl radicals and oxygen atoms. Plasma-treated samples had higher dye uptake, and better antibacterial properties against S. aureus. The samples did not have antibacterial properties against E. coli.