Changes of Organized Solution (Microemulsion) Structure with Small Change in Amphiphile Composition

Abstract

In the system of 8wt% CaCl₂ aq./C₁₂H₂₅OCH₂CH₂SO₄Ca_0.5/i-C₈H₁₇OCH₂CH (OH) CH₂OH/decane with only 3wt% of total amphiphiles, it was possible to obtain only one phase region of microemulsion whose solvents swelled by 97wt% (water+oil). The composition of water and oil varied over the entire range with slight changes in the amphiphile ratio from 0.380.42.
The self-diffusion measurements indicated the microemulsion microstructure to change from O/W, a hydrophilic conditions to W/O, a lipophilic condition via bi (tri) continuous with change hydrophile-lipophile balance of the amphiphiles.
From a comparison of these results with change in temperature in a nonionic surfactant system, it is evident that the change in the ratio of hydrophilic amphiphile and lipophilic amphiphile, from 0.38 to 0.42 in the present study has the same effect as that in HLB by making the temperature 30°C in the nonionic surfactant system.