What factors affect the color of the dye?

External factors such as solvents, temperature, dye concentration, electrolytes, and radiation light added to the dyeing solution will cause dyes in the solution, or the state of the dye fabric changes, resulting in changes in the color of the dye.

1. The effect of solvent and medium

The absorption wavelength of the dye solution changes with the size of the solvent. When the dye is dissolved in the polar solvent, the polarity of the dye increases with the increase of the solvent polarity, thereby reducing the stimuli, moving the absorption wavelength towards the long wave, and the color of the dye solution deepen.

Many solvents can also generate hydrogen bonds and solvents with dyes, which will change the color of the dye solution.

The color of the dye on the fiber (except for optical factors, such as scattering and the refraction of different fibers) different from the polarity of the fiber. Generally speaking, the color is darker on the fiber with high polarity, and it is lighter on the fibers with lower polarity. For example, decentralized dyes should be shallow on polyamide fiber on the polyamide fiber; cedic dyes are shallower than polyacryonal fibers on polyester fibers.

The pH value of the solution is different, which will change the properties of the electron or electronic group in the dye molecular coexistence system and change the color of the dye. For example, alkaline green will change from the original green solution to white precipitation in the alkaline solution, and then return to the original green after adding acid.

The position of amino or hydroxyl groups in the dyes in dyes in dyes is different. When the pH value of the solution changes, the color of the dye also has a different effect. This nature can be used as acidic and alkaline indicators. For example, the Congo in the direct dye is red, which is red in the water, and the acid becomes blue, and the alkali becomes red.

2. The effect of concentration on color

When the dye concentration is very small, the dye exists in a single molecular state in the solution. However, if the dye concentration increases, the dye molecules will gather into di agents or polyettes. The stimulation of the π electrons of the aggregate molecule can be higher than that of the single molecule, so the dye absorption spectrum moves in the direction of the short wave, and the color is lighter. For example, the λmax of Crystal Purple Single Molecular Status is 583nm, and its binary λmax is 540nm. The degree of dye gathered on the fiber also affects the color of the fabric. The fabric with insoluble nitrogen dyes and reducing dye dyes is used to change the color of the color after soap.

3. The effect of temperature on color

Change of temperature will affect the tendency of dyes, and then promote the color of the dye. When the temperature rises, the degree of aggregation of the dye decreases, and the absorption wavelength moves towards the direction of the long wave, which has a dark effect. The colors of some organic compounds and dyes will change with temperature. This phenomenon is called thermal deformation.

4. The effect of light on color

Some even nitrogen, sulfur, and Jingyin dyes exist at a stable and transformed structure at normal temperature. Under the light, the transforming structure of the dye will become a cash -type structure. When the light source leaves, the smooth structure will be replied to it again to be the background structure. Capable structure. The dye absorption spectrum of transliteration and cashmere structure is different, and the color displayed is also different. This phenomenon is called optical degeneration.