UNILAMELLAR LIPID BILAYERS AS VEHICLES FOR AZO DISPERSE DYES ON WOOL

Unilamellar phospholipid vesicles have been examined as carriers for a zo disperse dyes applied to untreated wool fibers. Liposomes were prep ared with egg phosphatidylcholine and contained CI disperse orange 1 a t different phospholipid/dye concentrations. The physical stability of these systems was assessed by measuring the mean vesicle size distrib ution of liposome suspensions after preparation and during the dyeing process. Kinetic aspects involving dye adsorption and bonding on untre ated wool samples by means of unilamellar liposomes at different dye/l ipid molar ratios were also investigated. This process leads to the co ntrolled exhaustion of dye in wool fibers, which depends directly on t he relationship existing between the dye and phospholipid components i n liposomes, improving dye adsorption and dye-fiber bonding. The dispe rsing efficiency of these systems as regards the use of conventional d ispersing agents has been also improved. The optimum application for b oth dye exhaustion and total amounts of dye bonded to the untreated wo ol fibers correlates directly with the dye/phospholipid weight ratio, corresponding to the maximum level of dye encapsulation efficiency of these systems in the range of phospholipids and dye studied.