Stabilization of natural and synthetic indigo on nanocellulose network - Towards bioactive materials and facile dyeing processes

Synthetic dyes are vastly used for colouring numerous materials, although the adverse effects on environment well recognized. In addition to developing existing dyeing technologies more efficient and cleaner, valorisation of natural can enhance sustainable development industry. Natural indigo, derived from Isatis tinctoria, is a bio-based alternative indigo produced via chemical synthesis routes. Owing insoluble character pigment, dye requires conversion into soluble leucoindigo form prior dyeing, which often accomplished by using harsh sodium dithionite vat technique. During processing plant attached fabric, transferred oxidized once back leucoindigo. Additionally, oxidation difficult control with traditional technique maintaining through adding reducing agent chemicals. Maintaining throughout process would enable lower number steps reduce use harmful agents. present study, stabilization nanocellulose matrix carrier was investigated spectroscopic photophysical methods. According results, successfully stabilized suspension, most likely due limited rate oxygen diffusion viscous medium. Visual observations revealed that leuco-form retained even longer than synthetic indigo. This enhanced stability attributed presence radical scavenging species in since did not show notable antioxidant properties. Given promising results paste formulation demonstrated be applicable creating patterns cotton screen-printing Since carrier, need re-reduction avoided amount chemicals reduced. These findings also characteristics considered disadvantageous compared dyestuff, i.e. co-products mixture, however, create value dyed material new functionalities.