Abstract:

In order to develop pH-sensitive color changing fabrics, the influence of pH on the color change of fabrics of fabrics dyed by turmeric were studied. The main chemical compositions of dye extracted from turmeric were analyzed by high performance liquid chromatography (HPLC). The absorption spectra of turmeric solution at different pH values were tested. The dye uptake and the color fastness of fabric dyed by trumeric were measured. The color changing properties at different pH values of samples of samples dyed by turmeric were evaluation by means of the values of CIELAB. The results show that the main chemical component of vegetable dye extracted from turmeric is curcumin. The curcumin molecules are ionized into anions under alkaline conditions, and the color of curcumin changes. With the pH value of the solutions increasing, the absorption peaks of the trumeric extraction solution have red shift and the absorption intenstity increases. The color of the turmeric extraction solution is yellow under acid condition. When the pH wvlue of the cxtracted liquid is greater than 8, the solution color is reddish brown. The dyeing property of curcumin for silk fabric is better than for cotton fabric. The color of fabric dyed by curcumin has a significant change when the pH walue is changed from neutrality to alkality. The hue value becomes lower, and the fabric color changes from yelow to red.

Key words: color changing fabric, turmeric, vegetable dye, pH-sensitive color changing