الفهرس | Only 14 pages are availabe for public view |
Abstract The thesis aims to study the solvation parameters of sodium dodecyl sulfate (SDS), Sodium Lauryl Ether Sulfate (SLES), Cocamidopropyl Betaine (CAPB), Alkyl Benzyl Dimethyl Ammonium Chloride (BAC) and Cetyl Trimethyl Ammonium (CTMA) surfactants using different measurements such as; conductivity, surface tension, density, and refractive index. The density and refractive index measurements was used to estimate addition physical properties of the surfactants. Conductivity of the five surfactants solutions in aqueous and in alcoholic-aqueous mixed solvents with different mole fractions of alcohols has been measured experimentally at different temperatures. Surface tension was also measured experimentally for the five surfactants in aqueous solution at 298.15 K. Critical micelle concentration (CMC) of the five surfactants was determined from the measured conductivity and surface tension data. The CMC was found to increase as the temperature and alcohol mole fraction increased in all solvents used. Depending on the conductivity data, the association constant (Ka) was also determined applying Shedlowsky conductance equation. The thermodynamic parameters (ΔG˚, ΔH˚, and ΔS˚) of the micellization and association processes were evaluated from the temperature dependence of micellization and association constants. The results indicate that the association constant of this surfactants decrease as the temperature and alcohol mole fraction increased in all solvents used, also the association process was found to be spontaneous one. The density and refractive index of the five surfactants solutions in aqueous and in alcoholic aqueous mixed solvents with different mole fractions of alcohols, has been measured experimentally at 298.15 K. It was found that the densities values of SDS, SLES, CAPB, BAC and CTMA surfactants solutions was decrease as the alcohol mole fraction increased in case of ethanol-water and methanol-water, while in case of glycerol-water solvents it increase with increasing the alcohol mole fraction. Also depending on the refractive index data, the molar refraction and the polarizability of the five surfactants is increase as the mole fraction of ethanol, methanol and glycerol increase. This increase in may be related to the increase in the apparent molar volume of the SDS, SLES, CAPB, BAC and CTMA surfactants with the mole fraction of alcohol. |