Phase Behavior of Dodecyl Dimethyl Amino Oxide/Sodium Dodecyl Sulfate in the Presence of Perfluorooctanol

Abstract

The ternary phase diagram of dodecyl dimethyl amino oxide (C₁₂DMAO) perfluorooctanol (C₇F₁₅CH₂OH) – H₂O, sodium dodecyl sulfate (SDS) – (C₇F₁₅CH₂OH) – H₂0, C₁₂DMAO/SDS (66/33, w/w) – (C₇F₁₅CH₂OH) – H₂0, and C₁₂DMAO/SDS (33/66, w/w) – (C₇F₁₅CH₂OH) – H₂0 systems have been studied. The identification of the phases was done by macroscopic observation of the sample either by naked eye or through crossed polarizers. For further characterization of the phases, different techniques were used such as electrical conductivity, polarization microscopy, ²H-NMR, and small angle X-ray scattering. The microstructure resulting from the self assembly of the surfactant can vary from normal micelle (L₁), lamlar liquid crystal (Lα), to reverse micelles (L₂), as relative volume fraction of apolar component increases over that of polar component.

ACKNOWLEDGMENT

We are indebted to Prof. H. Hoffmann of Bayreuth University, Germany, for providing the chemicals and supporting this work. Our thanks are extended to Al-Azhar University, especially the chemistry department, where this work was conducted in the physical chemistry research laboratory.