Micelle Formation by Lecithin in Some Aliphatic Alcohols

Abstract

Lecithin has been studied in methanol, ethanol, butanol, and hexanol using light scattering and viscosity techniques. A new type of light scattering cell was employed. Micelles were present in all solvents, the micellar weights being 2,300; 7,100; 18,000, and 22,000 in the four alcohols respectively. It appeared that as the polarity of the solvent decreased, the micellar size increased. Dissymmetry measurements showed that no dimension of the micelles exceeded 270Å (λ/20), but high observed depolarisations showed that the particles were anisotropic. Viscosity measurements also gave an idea of the shape of the micelles, giving intercepts of plots of specific viscosity/solute volume fraction against solute volume fraction of 4.29, 4.26, 4.26, and 3.56 for the four alcohols respectively. Using the dimensions of the lecithin molecule, and the number of monomers present in the micelle, calculations of the theoretical viscosity intercept have been made for each solvent, and compared with values obtained experimentally