Penetration of Alcohols into Wool and Hair as Studied by Fluorescence Microscopy

Abstract

We have investigated a dye diffusion method for monitoring the penetration of solvents into keratin fibers. The lipid stain, Nile red, is a useful probe for this purpose. Differences in the penetration of aliphatic alcohols into dry wool, as revealed by the extent of dye penetration, correlated well with the known variation in sorption rate for solvent molecules of varying molecular size and shape. We examined the penetration of various animal fibers by t-butanol using the same technique. The cortex of human hair was readily penetrated by t-butanol, while the cortices of wool, mohair, and cashmere fibers showed no penetration under the same conditions. However, we did obtain evidence for penetration by t-butanol of the intercellular material between the cuticle cells of these fibers.