Plasma‐assisted bio‐based modification of silk fabric for enhanced inkjet printing quality and antimicrobial activity

Silk is distinguished by lightweight texture and limited water retention, leading to a light colour and fuzzy pattern during inkjet printing. Due to its proteinaceous nature, silk is susceptible to bacterial growth, which significantly impacts its functionality and poses health risks. To mitigate these issues, the silk fabric was initially subjected to plasma irradiation, followed by sequential immersion in tannic acid (TA) and chitosan (CS) solutions. This process formed a TA/CS biomass film on the fabric surface, imparting antibacterial property and resistance to ink infiltration. Subsequently, the modified silk underwent inkjet printing with gardenia blue ink, fixation through steaming, and thorough rinsing. Analyses using scanning electron microscopy, X‐ray photoelectron spectroscopy and X‐ray diffraction confirmed the successful application of TA and CS without altering the primary structure of silk fibres. Under the specified modification conditions (plasma treatment 180 s, TA concentration 10 g/L, and CS dosage 2%), the printed silk exhibited a deep blue colour with a colour strength of 6.3 and demonstrated colourfastness to rubbing and washing at a grade of 4 or higher. The printed pattern was precise, with a variation in line width of less than 10% in both warp and weft directions. Moreover, the printed fabric showed a 95% antibacterial efficacy against E. coli and S. aureus , and achieved a free radical scavenging rate of 71% even after 10 soapings. Overall, this study presents a straightforward, effective, and sustainable modification approach to enhance the inkjet printing quality and antibacterial property of silk fabrics.