Phosphatidylcholine unilamellar liposomes as vehicles for a 1:2 metal-complex dye in wool dyeing

Studies on the use of large unilamellar liposomes of defined size (400 nm) as carriers of a 1.2 metal-complex dye for untreated wool fibres are described. Liposomes made from egg phosphatidylcholine (PC) containing CI Acid Ye[tow 129 (weakly polar) were investigated. The total lipid concentration of liposomes varied from 0.56 to 6.81% o.w.f (corresponding to 0.25-3.0 mmol/l) and the dye concentration from 0.1 to 1.0% o.w.f. The physical stability of these systems was assessed by measuring the mean vesicle size distribution of the suspensions after preparation and during dyeing. Kinetic aspects involving dye adsorption and bonding on untreated wool samples were also investigated. This process led to the controlled exhaustion of dye on wool samples, which was dependent on the PC concentration and on the PC/dye weight ratio in the liposomes. At a constant dye concentration a progressive rise in the dyebath exhaustion took place as the PC concentration in bilayers increased.