EFFECT OF NACL ON A NONIONIC SURFACTANT MICROEMULSION SYSTEM

Various types of microstructure and macroscopic phase changes of the p seudoternary system alkane/Brij 35 + propanol/water, studied in presen ce of different amounts of sodium chloride at different temperatures, are presented and discussed in this paper. Viscosity and conductance s tudies reveal that the system at 80% surfactant (S), where S indicates BriJ 35 and 1-propanol together, probably exists as a bicontinuous mi croemulsion at all water fractions even in the presence of NaCl. In th e presence of NaCl, Pseudoternary phase diagrams of the system changes with change of temperature. Increase of the concentration of NaCl bri ngs down the Winsor I --> III transition temperature and at 2.5 M NaCl the system exists as Winsor III along the entire range of temperature studied (30-70 degrees C). However a Winsor III --> II transition was not observed in this case in this temperature range and also within t he NaCl concentration range studied. The cloud point of the microemuls ions and the contact angle of these systems with a Teflon surface were also determined and discussed. The contact angle values indicate simi lar structure over the whole range of the oil/water ratio.