화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.107, No.50, 13862-13870, 2003
Light, neutron, X-ray scattering, and conductivity measurements on aqueous dodecyltrimethylammonium bromide/1-hexanol solutions
Ternary systems of dodecyltrimethylammonium bromide (C(12)TAB)/1-hexanol/water are examined for series with constant surfactant to alcohol molar ratios of n(s)/n(a) = 8:2, 8:4, 8:6, and 8:8 at surfactant concentrations of c = 6.167-61.67 g/L (0.02-0.20 mol/L). The methods used are conductivity measurements, differential refractometry, static and dynamic light scattering, small-angle neutron scattering, and X-ray scattering. Critical micelle concentrations (cmc) and the degree of dissociation of the micelles are determined by conductivity measurements. The refractive index increment is given for each series as well as static and dynamic light-scattering intensities plotted as a function of the surfactant concentration. From small-angle neutron-scattering experiments a detailed picture of the size and the geometry of the micelles could be obtained, whereas small-angle X-ray scattering allowed information about the thickness of the interfacial film to be inferred. A hypernetted chain calculation with solvent plus ion-averaged screened Coulombic potentials combined with an ellipsoidal core/shell model permitted a simultaneous and coherent description of all scattering results.