Ionic Liquid Modification of Acidic Dyes for Impermeable Inkjet Printing on Untreated Polyamide Fabrics

This study introduces a novel approach to inkjet printing on untreated polyamide fabrics (Nylon-66), leveraging the power of ionic liquids to enhance acid dye performance. By replacing sodium ions in Acid Big Red G and Acid Carmine dyes with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), ink impermeability and dye-fiber bonding on nonpretreated fabric were improved significant on unpretested Nylon-66. The modified inks demonstrate reductions in line widths (24.75% for Dye G and 33.95% for Dye R) and substantial increases in <i>K</i>/<i>S</i> values (43.24% and 24.83%, respectively), while maintaining consistent CIE color coordinates. The innovation lies in the superior performance of imidazolium cations over traditional sodium ions, resulting in enhanced ionic bonding and reduced ink bleeding. This discovery is attributed to the larger ionic radius and increased positive charge density of the ionic liquid, facilitating stronger interactions with polyamide fibers. Crucially, the method eliminates the need for fabric pretreatment, simplifying the printing process and significantly reducing environmental impact by minimizing wastewater generation. This innovation not only advances digital inkjet printing technology but also offers a more sustainable and efficient solution for high-quality textile printing without compromising color vibrancy.