Interaction between Ionic and Nonionic Surfactants in the Adsorbed Film and Micelle. Dodecylammonium Chloride and Tetraethylene Glycol Monooctyl Ether

Abstract

The surface tension of aqueous solutions of dodecylammonium chloride (DAC) and tetraethylene glycol monooctyl ether (C8E4) was measured as a function of the total molality of surfactants and the composition of C8E4 at constant temperature under atmospheric pressure. The results of the surface tension measurements were analyzed by our thermodynamic procedure, and phase diagrams of adsorption and micelle formation were drawn. The miscibility of the surfactants and their intermolecular interaction in both the adsorbed film and the micelles were examined. Deviation from ideal mixing was observed and an attractive interaction was suggested. Furthermore, the phase diagram of micelle formation was shown to have an azeotropic point, and a stronger energetic stabilization was suggested in the mixed micelle formation than in the adsorbed film at the cmc. This difference suggests that the structures of both the surfactant molecules and the aggregates significantly affect the intermolecular interaction between surfactants.

Apparent Binding Degree of a Counterion and Micellar Composition in Cationic and Nonionic Surfactant Mixed Solutions at CMC

“…Equation [27] corresponds to the expression for the phase separation model except for the term (V sm /RT ) dπ (11,23). We can rewrite Eq.…”

“…A number of solution properties for mixed surfactant systems have already been published (1). In the last five years, several papers on mixtures of nonionic and ionic surfactants using capillary electrophoresis (2), molecular thermodynamic theory (3), potentiometry (4), regular solution theory (5,6), small-angle neutron scattering (7)(8)(9), surface tension (10,11), ultrafiltration (12,13), volumetry (14), and so on have been also published. 1 Fax: +81-93-693-3201.…”

Phase Transition and Miscibility of Binary Surfactant Mixtures in Adsorbed Film at the Air/Water Surface

“…The reason whym andX 2 are used as a concentration and a composition instead of m = m 1 + m 2 and X 2 = m 2 /m is that the choice of m and X 2 for independent variables causes a thermodynamically analytical error, for instance, disagreement between X H 2 and X 2 at the azeotropic point (24). The surface tension γ of the aqueous solution at constantX 2 is shown as a function ofm in Fig.…”

“…We have evaluated the activity coefficients and the excess Gibbs energy of adsorption and micelle formation for several binary surfactant mixtures and examined the miscibility and interaction of surfactants in adsorbed films and micelles quantitatively (15)(16)(17)(18)(19)(20)(21)(22). One of the important conclusions derived from our previous studies is that the strong interaction between tetraethylene glycol monooctyl ether (C8E4) and DAC molecules in the adsorbed film and micelle is due to the surfactant cation-dipole interaction or the hydrogen bond between the ammonium ion and the oxyethylene group (23)(24)(25).…”

The role of charged surfactants in the thermal and structural properties of lyotropic liquid crystalline mesophases of [Zn(H2O)6](NO3)2?CnEOm?H2O

“…The fundamental question is how one can increase the metal ion density to 6-7 metal ion/C n EO m mole ratios without disturbing the LC phase. It is known that charge surfactants, such as CTAB and SDS can be used together with the non-ionic surfactants or Pluronics in the LLC mesophases and micelle phases [19][20][21][22][23][24][25]. The hydrophobic interactions (among alkyl chains of both charged and non-ionic surfactants) and the hydration of the alky tail-ethylene oxide interface with the help of a charged head group enable the assembly of two or three surfactants into a single mesophase.…”