Surface Properties and Micellar Molecular Interaction in Binary Systems of a Biosurfactant Sodium Deoxycholate (NaDC) with Conventional Surfactants

Abstract

Surface tension for the binary mixtures of a biosurfactant sodium deoxycholate (NaDC) with three different conventional surfactants (p-(1,1,3,3-tetramethylbutyl)phenol polyoxyethylene, polyoxethylene-10-oleyl ether, and sodium oleate) were measured in buffer solutions at different temperatures. Surface properties were determined as well as the micellar characteristics like composition, micellar molecular interaction parameter (b), activity coefficients (f 1 , f 2 ), and the free energy of micellization were analyzed using some theoretical models, including Clint, Rubingh, Motomura and Maeda models. The results reveal that all the three investigated systems show non-ideality in the micelle formation by the deviation in the experimental critical micelle concentration (CMC), f 1 , f 2 , and negative b values from the ideal values. The proportion of NaDC in the mixed micelle (X 1 ) calculated by all models increases with increasing the molar fraction of NaDC in solution (a NaDC ), but the X 1 values are very small even at the high a NaDC . Moreover, by using the Maeda theory, the results suggest the chain-chain interaction among surfactants does not seem to be strong. It is noted that two break points were observed in the surface tension plots of pure NaOL and NaDC/NaOL mixture solutions. Interestingly, by introducing moderate NaDC or decreasing the temperature, the first break point disappeared for the two systems.

Surface properties, micellar molecular interaction, and physical properties for binary systems of sodium oleate with three anionic surfactants

“…According to the Eqs (1) and (2), the values of Г max and A min for these mixed systems are calculated and listed in The values of A min decreased with increasing in α NaOL for NaOL/ NaDC and NaOL/AOT systems, which indicated an increased concentration of NaOL on the surface adsorption layer. In our previous studies, for the NaDC/NaOL system in buffer solution (pH 10), the A min values initially increase and then decrease when α NaDC exceeds 0.33 [10] .…”

“…In this case, the surface properties of the mixed surfactants are better than those of the individual ones [9] . The common methods used to study mixed surfactants include surface tension [10] , conductivity [11] , fluorescence [12] , small angle neutron scattering [13] and surface partitioning [14] . In recent years, the researches on NaOL mixtures have expanded in various fields.…”

Curcumin-Encapsulated Hexagonal Liquid Crystalline Formed by Brij 97/NaDC Mixtures

“…The previous investigations of this surfactant revealed that Brij 97 had abundant phase behaviors, and formed various liquid crystals including lamellar, cubic, and hexagonal phases with different additives. [15][16][17] In our recent work, [18] it was found that a strong interaction exists among Brij 97 and NaDC molecules and the mixed micelle formed in this system is quite stable.…”

MesoDyn prediction of a pharmaceutical microemulsion self-assembly consistent with experimental measurements

“…2 In our previous studies, Brij97 could form various aggregates including micellar, 3 microemulsion, 4 lamellar, 5 hexagonal 6,7 and cubic 8,9 liquid crystals. Although the formation conditions of various Brij97-based aggregates have been shown clearly, the detailed information of the self-assembled process of Brij97 in the oil-water interface at the nanometer scale 10 is difficult to obtain from experiments.…”