Optimization of Process Conditions of Cotton Fabric Dyeing with Nettle Leaf Extract for Antibacterial Application Using Central Composite Design

Abstract

ABSTRACT In this study, all conditions of the natural dyeing process of cotton fabric with antibacterial efficiency, extracted from the leaves of the nettle were optimized using a central composite design. The optimized dyeing conditions are: concentration of 16.943 g, temperature of 50 °C, time of 40 min, and the color strength obtained at optimum condition was 1.53. The Nettle natural dye is applied to cotton fabrics by the Pad-Dry-Cure method for imparting antibacterial properties to the textile product for apparel applications. Biomordants were applied on scoured cotton fabric in the pre-mordanting process of dyeing. Color characteristics of the dyed fabrics were measured by CIE L*a*b* value using a spectrophotometer. Gram-positive (S. aureus) and gram-negative (E. coli) bacterial assessments were performed quantitatively using the AATCC-100 test method. The results provided evidence that the treated fabric exhibits higher antibacterial efficiency of gram-positive and gram-negative bacteria by 96.5–98% reduction compared to the control samples, respectively. The one having the highest antibacterial activity was washed 15 times under the same conditions and samples were taken after 1, 5, 10, and 15 washes. They retained nearly 91% S. aureus and 94% E. coli activity up to 10 launderings against the two bacteria.