A 4-COMPONENT PHASE-DIAGRAM

A complete phase diagram was determined for the system water, decane, isostearic acid, and triethanolamine using optical microscopy and low- angle X-ray diffraction. The system contained two isotropic liquids in the form of an isostearic acid/decane solution with dissolved trietha nolamine as well as a water/triethanolamine solution with dissolved is ostearic acid and decane. Two lyotropic liquid crystals were found, on e of lamellar structure and one consisting of a hexagonal array of clo se-packed cylinders. Of the two-phase spaces connecting the two liquid s with the lamellar liquid crystal one was initiated toward the aqueou s solution/decane line, while the other on emanated from the decane/is ostearic acid/triethanolamine plane.