Confocal Raman depth imaging tracking on the diffusion process of single and two-component reactive dyes in a single viscose fiber

Confocal Raman microscopy (CRM) was used as a non-destructive tool for in situ investigations of the diffusion process of C.I. Reactive Blue 194 (RB194) and C.I. Reactive Yellow 176 (RY176) in single fibers. Mapping along the radius of the fiber was performed. The distribution of dye in the fiber at different adsorption time was observed. A significant dye concentration gradient was obtained along the line normal to the fiber surface to a depth of 6?m as a function of depths. The diffusion process of a single dye with different initial concentrations in fibers was first studied. The results showed that the diffusion rate of dyes in the fiber is mainly affected by the initial dye concentration and the affinity between dye and fiber. In the mixed dyes, RB194 having a higher affinity with fiber is less affected by other factors, and its diffusion rate in the fiber mainly depends on the driving force provided by it concentration difference. The diffusion of RY176 with lower affinity and easier aggregation in fiber is easily affected by other factors, such as concentration or other components in color matching. In this study, RB194 in the mixed component has a strong promotion effect on the diffusion of RY176 in the fiber. The distribution of dye in the fiber can judge the permeability and uniformity of the fabric during dyeing. The diffusion properties of different dyes in the fiber can be analyzed more directly and accurately to promote the design and development of dye molecular structure.

Automated summary

Confocal Raman microscopy was used to study the diffusion process of CI Reactive Blue 194 and CI Reactive Yellow 176 in single fibers, revealing that the initial dye concentration and the affinity between dye and fiber are the main factors affecting diffusion rate.