The Effects of Halides on the Phase Behavior of CTAB-AS-H_2O Mixed System

The phase behavior of cetyltrimethylammonium bromide(CTAB) and sodium dodecyl sulfonate(AS) mixed system in dilute aqueous solution region has been studied.The effects of NaF,NaCl,NaBr and KCl on the phase behavior have been investigated.The results indicate that two aqueous two-phase regions can be formed at 318.15 K for CTAB-AS mixed system in aqueous solution or in 0.10 mol·kg~(-1) brine.Every aqueous two-phase region is surrounded by one isotropic single-phase region and one liquid crystalline single-phase region,between the two liquid crystalline single-phase regions,there is one heterogeneous phase region.The addition of inorganic salt results in the enlargement of heterogeneous phase region and aqueous two-phase regions,meanwhile,the aqueous two-phase regions shift to the adjacent isotropic single-phase regions.