Effect of counterions on the structure of reverse micelles according to the data of molecular-dynamic simulation

An AOT reverse micelle in a medium of supercritical carbon dioxide

“…4, 5) is similar to that obtained for a micelle in the medium of a nonpolar hydrocarbon [33]. The positions of the peaks are almost the same; however, their heights and the values of the coordina tion numbers (Table 2) are larger than those found for the micelle in the nonpolar solvent [33].…”

“…The profile of the partial densities of water and SCCD shows some penetration of water molecules onto the external side of the micelle (Fig. 2), where the mixing of the two solvents takes place, which has not previously been observed for a hydrocarbon [32,33]. Distributions at which the charged head groups of the surfactant and counterions were located only in the aqueous cavity of the aggre gate were obtained in [32,33].…”

“…2), where the mixing of the two solvents takes place, which has not previously been observed for a hydrocarbon [32,33]. Distributions at which the charged head groups of the surfactant and counterions were located only in the aqueous cavity of the aggre gate were obtained in [32,33]. The replacement of the nonpolar solvent by carbon dioxide, the molecules of which have their own quadrupole moment, facilitates the penetration of surfactant ions into the solvent.…”

“…The eccentricity value was 0.43, which was substantially lower than that of a micelle with the same composition in the medium of a hydrocarbon (e = 0.56) [33]. Moreover, the visual observation of the system showed slight fluctuations of the aggregate sur face, which were accompanied by mixing of the two solvents in the surfaced layer.…”

“…4, 5). As can be seen from the comparison of the profiles of the partial densities of AOT force centers with those obtained in [33], the replacement of a nonpolar solvent by SCCD has resulted in widening of the polar core. Two resolved peaks are seen in the density profile of the head groups of surfactant ions (curve 1).…”