Chemistry

Enhanced Dyeing

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Science  02 Apr 2004:
Vol. 304, Issue 5667, pp. 18-19
DOI: 10.1126/science.304.5667.18e

Traditional methods for dyeing wool use elevated temperatures that damage the fibers and require absorption enhancers that create pollution concerns. The dyeing and diffusion properties of the wool fibers are governed by the internal wool lipids that hold the cells together, and thus an understanding of how the dyeing process changes these structures is key to its optimization.

Liposomes, which consist of a water droplet surrounded by a bilayer of lipids, have been shown to enhance the dyeing process. Martí et al. examined the influence of phosphatidycholine (PC) liposomes on the absorption of two dyes: hydrophilic acid green 25 (AG25) and hydrophobic acid green 27 (AG27). When the PC liposomes were added to the bath, they enhanced the absorption of AG25 but diminished that of AG27. However, when the fibers were first pretreated with liposomes, dye absorption was increased in both cases. During the dyeing process, polar lipids are removed from the wool. Liposome pretreatment enhanced the release of the polar lipids, and the liposomes were also absorbed into the fibers. The combined change to the wool cell membrane structure is what leads to enhancement of the dyeing process. — MSL

Langmuir 10.1021/la030385+ (2004).

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