The correlation of the structure and phase behavior between sodium citrate/sodium lauryl benzene sulfonate/pentanol/water and sodium p-toluene sulfonate/sodium lauryl benzene sulfonate/pentanol/water systems

Abstract

We present experimental results that show that a salting-out effect takes place for the SPTS/NaLAS/Pentanol/H 2O (SPTS, sodium p-toluene sulfonate; NaLAS, sodium lauryl benzene sulfonate) system at a concentration of NaLAS greater than 1.5% wt. but for the SC/NaLAS/Pentanol/H 2O system (SC, sodium citrate) only at a concentration of NaLAS greater than 21.6% wt. In addition, lamellar liquid crystals are found to be present in the system SPTS/NaLAS/pentanol/H 2O at an NaLAS concentration greater than 13.5% but are found in the system SC/NaLAS/pentanol/H 2O at an NaLAS concentration greater than 8.1% wt. More importantly, the sizes of lamellar liquid crystals are observed to be much smaller for the system SC/NaLAS/pentanol/H 2O than for SPTS/NaLAS/pentanol/H 2O and are definitely associated with the concentration and type of salts being used in the system.