Incorporating Antimicrobial Activity During Synthesis of New Acid-Azo Dyes: Thermal Stability and Application on Various Fabrics

Abstract

Background: Textile materials are susceptible to microbial attack as they provide suitable conditions for their growth. The microbes grow with normal body secretions on garments. These microbes are responsible for the weakening, brittleness, and discoloration of the substrate. Furthermore, they cause many health issues to the wearer, including dermal infection, bad odour etc. They threaten the human health as well as create tenderness in fabric.

Objectives: Usually, antimicrobial textiles are prepared by applying antimicrobial finishes after dyeing, which is an expensive approach. Concerning these adversities, in the present study, a series of antimicrobial acid-azo dyes have been synthesized by incorporating antimicrobial sulphonamide moiety into the dye molecules during its synthesis.

Methods: A commercially available sulphonamide-based compound, sulfadimidine Na-salt was used as a diazonium component and coupled with different aromatic amines to get desired dye molecules. Since dyeing and finishing are two separate energy-intensive processes, in the current research work, an approach to combine both processes in one step has been adopted that would be economical, timesaving, and environment friendly. Structures of the resultant dye molecules have been confirmed using different spectral techniques such as Mass spectrometry, ¹H-NMR spectroscopy, FT-IR, and UV-Visible spectroscopy.

Results: Thermal stability of the synthesized dyes was also determined. These dyes have been applied to wool and nylon-6 fabrics. Their various fastness properties were examined using ISO standard methods.

Conclusion: All the compounds exhibited good to excellent fastness properties. The synthesized dyes and the dyed fabrics were screened biologically against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 10536, resulting in significant antibacterial activities.

Keywords: Antibacterial acid-azo dyes; atomic force microscopy (AFM); color fastness properties; functional dyes; sulfadimidine Nasalt; thermal stability.