PHASE-BEHAVIOR AND PROPERTIES OF A MICROEMULSION IN THE PRESENCE OF NACL

The effect of salinity, particularly high NaCl concentrations, on the phase diagram of the pseudoternary system cyclohexane/sodium dodecyl s ulfate + propanol/water was studied at various temperatures. Drastic c hanges were observed with increasing salinity and a three-phase zone a ppears at approximately 1 M concentration. At still higher concentrati ons only two-phase regions remain. The volume measurement with increas ing salinity reveals three types of Winsor formations (Winsor I, II, a nd III). The optimal salinity determined by plotting solubilization pa rameters of oil V(o)/V(m) and that of water V(w)/V(m) against NaCl con centration declines with temperature increment and attains a constancy above 70-degrees-C. Physicochemical properties, viz. conductance, vis cosity, and adiabatic compressibility, investigated for a one-phase mi croemulsion in the presence of NaCl prove the existence of W/O, O/W, a nd bicontinuous structures in the system. An unexpected and surprising decrease in the conductivity of W/O samples with elevation in tempera ture was also noticed.