Karl D. Dreher

Structure and specific counter ion effects of nonadecylbenzenesulfonate monolayers

Nonadecylbenzene-p-sulfonate monolayers were examined on a variety of substrates. The surface potential for nonadecylbenzene-p-sulfonate was significantly higher than that of an alkyl sulfonate. In the ionized form, the benzene ring did not inhibit close packing in the monolayer; collapse occurred at approximately the same area/molecule as the alkyl sulfonate. Specific counterion effects were observed also. Monolayers of nonadecylbenzene-p-sulfonate were expanded in the order K < NH4 < Na < Li and Sr < Ca < Mg.

Rheological properties of fluids composed of an alkylbenzene sulfonate, decane, cyclohexanol, and water

Abstract Rheological properties of a concentrated surfactant system were determined. Flow curves for a fluid composed of an alkylbenzene sulfonate, hydrocarbon, water, and cosurfactant were obtained as a function of the amount of water added to the system. All fluids were optically clear and phase stable. Compositions that can be classified as oil-external microemulsions were found to exhibit Newtonian flow behavior. Non-Newtonian flow was observed for those compositions that were in the oil-external to water-external transition region. Certain compositions in this region showed a discontinuity in the flow data suggesting a sudden transition from the lamellar structure of the phase inversion region to spherical droplets of water-in-oil.

Cohesive forces between alkylaryl sulfonates at the air—water interface

Abstract Ammonium 2-(n-tetradecyl)-naphthalenesulfonate and ammonium 6-(n-tetradecyl)-1,2,3,4-tetrahydronaphthalenesulfonate were prepared by sulfonation of the appropriate hydrocarbons with SO3 vapor diluted in N2. Surface properties were studied by means of the monolayer technique. Force-area isotherms indicated that the naphthalenesulfonate forms a more strongly cohering monolayer than the 6-substituted tetralinsulfonate which is sterically hindered from close packing. These results are compared to those obtained for nonadecylbenzene-p-sulfonate.