Measurements of the surface tension of decylamine and perfluoroheptane and interfacial tension of water-perfluoroheptane were carried out. Measurements of the contact angle were also made for water, glycerol, formamide, diiodomethane, bromoform, and benzene on DACl and CsPFO layers formed on Teflon and on DACl and CsPFO pellets, as well as of zeta potential for surfactants adsorbed on latex. From the results obtained and the literature data the surface free energy of DACl and CsPFO for both tails and heads parts of their molecules, and their free energy of interaction through water were determined. It was shown that the free energy of interaction between -CH2- groups through water, determined from interfacial tension, is in agreement with that obtained from the relationship between logCMC and the number of carbon atoms in the chain of molecules of surfactants having the same head. It was also shown that there is agreement between the total free energy of interaction between molecules of surfactants through water and their critical micelle concentration (CMC).