Pioneering microsphere-dope dyeing for sustainable cellulosic fibre colouring

The textile industry has long been criticised for its high energy consumption, significant pollution, and low efficiency, highlighting the urgent need for sustainable innovations. This study presents an advanced approach to fabric dyeing by integrating microencapsulation with dope dyeing to enhance indigo retention in cellulose fibres. Encapsulating indigo within alginate-based microspheres prevents unwanted chemical reactions and minimises environmental impact. Microscopic and SEM analyses confirm the successful incorporation of indigo within fibres, significantly reducing dye loss (0.11-0.18 %) compared to traditional methods. Eliminating the need for reducing agents and oxidants simplifies wastewater treatment, while the fibres exhibit enhanced mechanical properties and exceptional wash durability, retaining 99.76-99.95 % of their weight after 20 cycles-comparable to pure cellulose fibres. A 48-h washing test further demonstrates excellent colour fixation, with minimal indigo detected in the washing solution (0.0042-0.0053 mg/L). By significantly reducing dye loss and chemical usage, this method offers a promising solution to minimising the environmental footprint of textile dyeing, particularly in cellulosic fibre applications. These findings highlight microsphere-assisted dope dyeing as a viable, sustainable alternative to conventional techniques, aligning with global sustainability goals while maintaining high-quality fibre production.