A. Ceglie, M. Monduzzi, O. Söderman
Mar 1, 1991
Citations
0
Influential Citations
7
Citations
Journal
Journal of Colloid and Interface Science
Abstract
Abstract A multifield 2H and 13C NMR relaxation study was carried out on some two-, three-, and four-component systems of sodium dodecyl sulphate in nonaqueous solvents such as formamide, N-methyl formamide, or N,N-dimethyl formamide. Pentanol or octanol was used as cosurfactant, while p-xylene was added to obtain nonaqueous microemulsions. Relaxation data were mainly analyzed in terms of a “two-step” motional model in order to obtain details on the structure and dynamics of the systems. The analysis of the data demonstrated some peculiar features of these nonaqueous systems, and analogies and differences with respect to the corresponding aqueous systems were investigated. It was shown that the degree of organization of SDS in the nonaqueous solvents is generally rather low. Among the results the effect of the addition of octanol as cosurfactant to the two-component systems should be mentioned. In the case of formamide systems, this alcohol seems to induce the formation of an organized solution, although the occurrence of any closed domain cannot be proved. A totally different behavior is observed in N-methyl formamide and N,N-dimethyl formamide. In these solvents, octanol seems to act as a structure breaker, thus leading to largely structureless solutions.