Interfacial tension of the lipid membrane formed from lipid-fatty acid and lipid-amine systems

Interfacial tension has been determined for phosphatidylcholine–stearic acid and phosphatidylcholine–stearylamine membranes. Phosphatidylcholine, stearic acid and stearylamine were used in the experimental. The interfacial tension values of the pure components are 1.62 × 10− 3 N/m, − 1.54 × 10− 2 N/m and 4.40 × 10− 3 N/m (hypothetical values), respectively. The 1:1 complexes were formed during formation of phosphatidylcholine–stearic acid and phosphatidylcholine–stearylamine membranes. The following parameters describing the complexes were determined: the surface concentrations of the lipid membranes formed from these complexes, A3− 1, the interfacial tensions of such membranes, γ3 and the stability constants of these complexes, K.