Assessment of print quality and coffee-ring effect acquired on wool and cotton fabrics inkjet printed with herbal inks

In this study, the ecologically pre-treated wool and cotton fabrics were digitally printed with eco-friendly plant-based inks of blue, red, yellow, and black colours obtained from the plant extracts of bio indigo leaves, quebracho red bark and the flame of the forest flowers. It was found that the Plasma Surface Treated (PST) wool and cotton fabrics exhibited improved print quality demonstrating clearer edges, sharp lines, and uniform solid patterns. The perceived uneven line and solid pattern were attributed to patchy pre-treatment. The plant-based inks constituted from the Quebracho red bark and the flame of the forest flowers extract both demonstrated reduced dispersion diameter (i.e. diffused) for the PST wool and cotton fabric than the untreated (NPST). These findings could be applied for digital printing on photonics to combat the Coffee-ring effect. The possible explanation for the reduced coffee ring effect is the phenomenon known as Marangoni flow. The predominant phytochemicals functioning as chromophores namely indigotin, tannin and butein enclosed in respective plant extracts are highlighted. The Life Cycle Analysis and assessment of functional phytochemicals on the resultant printed fabrics are suggested for future work.