Synthesis, Surface and Thermodynamic Properties of Substituted Polytriethanolamine Nonionic Surfactants

Three series of nonionic surfactants derived from polytriethanolamine containing 8, 10, and 12 units of triethanolamine were synthesized. Structural assignment of the different compounds was made on the basis of FTIR and H-1-NMR spectroscopic data. The surface parameters of these surfactants included critical micelle concentration (CMC), surface tension at the CMC (gamma(CMC)), surfactant concentration required to reduce the surface tension of the solvent by 20 mN m(-1) (pC (20)), maximum surface excess (I{''}(max)), and the interfacial area occupied by the surfactant molecules (A (min)) using surface tension measurements. The micellization and adsorption free energies were calculated at 25 A degrees C.