화학공학소재연구정보센터
Journal of Colloid and Interface Science, Vol.400, 59-66, 2013
A comparative study of micellization with fluorinated and hydrogenated diquaternary ammonium bolaamphiphiles
Two new N-a,N-b-Bis[3-(trimethylamino)propyl]-perfluoroalkanes diamide-lodide with (a = 1; b = 10) and (a = 1; b = 12), differing by the fluorocarbon tail spacer (8 or 10 -CF2-), and the N-1,N-12-Bis[3-(trimethylamino)propyl]-dodecanediamide-Iodide have been synthesized in two steps involving the appropriate dimethyl perfluoro or hydrogeno alkane dicarboxylate, N,N-dimethyl-1,3-propane diamine, and methyl iodide. Their surface properties were studied at 45 degrees C in aqueous solutions using conductivity, surface tension, and dynamic light scattering (DLS) measurements. A comparison of the micellar parameters usually obtained by these techniques has been carried out. The critical micelle concentrations (CMCs), the geometric packing parameters, the surface excess concentration, the area/surfactant molecule at the interface, the micellar ionization degree beta and the free energies of micellization, the diffusion coefficient, and the hydrodynamic diameter were discussed. The effect of added KI on these parameters and on the size and on the kind of aggregates has been also investigated. The addition of 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) to the surfactant solutions, where the size of the complex DOPE-surfactant was determined by DLS over a wide range of concentrations, reveals a very different behavior comparing fluorinated and hydrogenated compounds. (C) 2013 Elsevier Inc. All rights reserved.