Unimolecular films of lecithin and related compounds

Abstract

Unimolecular films of lecithin, lysolecithin, cholesterol, tripalmitin and triolein were examined by the method of surface potentials. The relative electric moments per molecule thus obtained are 8.8, 4.3, 45, 10.0, and 11.3 .10''18 e.s.u. respectively. Lecithin occupies 58 sq. A and lysolecithin 108 sq. A per hydrocarbon chain as an upper limit. Lecithin undergoes ion-ization at pH 3-6, and lysolecithin at 2-5. Mixed films of lecithin and cholesterol indicate no compound formation or dipole interaction. Homogeneous mixed films of triolein and egg albumen are obtainable, but not with tripalmitin and egg albumen.