Deposition of polyelectrolyte multilayers to improve the color fastness of silk

The color fastness to washing of silk fibers dyed with scarlet dye was improved by the deposition of a thin polymer film which prevented desorption of the dye in standard soap solution. Dyed silk fibers were coated with polyelectrolytes multilayers (PEM) by following the so-called layer-by-layer deposition method in which up to 30 layers of cationic poly(diallyldimethylammonium chloride) and anionic poly(sodium 4-styrene sulfonate) were deposited. The growth of the film was con firmed using attenuated total reflectance Fourier transform infrared spectrophotometry and the dye exhaustion from the silk fiber was monitoied using UV-Vis spectroscopy. The ability of the PEM to act as an electrostatic barrier against the release of the negatively charged dye was investigated as a function of the terminating top layer. The results showed that the negative layer-terminated PEM is more efficient at preventing the release of the dye than the positively terminated PEM.