Studies on the middle-phase microemulsion of lauric-N-methylglucamide

The middle-phase behavior and the solubilization power of the lauric-N-methylglucamide/alcohol/alkane/water quaternary system are studied. A series of phase inversions of Winsor Type I (2) → III (3) → II (2) emulsions are observed from the fishlike phase diagram. The compositions of the hydrophilic-lipophilic balanced interfacial layer in the middle of the middle-phase are calculated by the HLB plane equation. The effects of different alkanes, alcohols, and the concentration of an NaCl solution on the phase behavior and solubilization power are investigated, which indicates that alkanes with short hydrocarbon chains and alcohols with long alkyl chains have large solubilization power. The concentration of NaCI solution has a small influence on the solubilization power, whereas, the larger the NaCl concentration, the smaller the weight fraction of alcohol needed to balance the hydrophilic-lipophilic layer.