Property of Aqueous Two-Phase System Containing Alkyltrimethylammonium Bromides and Sodium Dodecyl Sulfate

The property of aqueous twophase system (ATPS) of cationic surfactant alkyltrimethylammonium bromides (DeTAB、DoTAB、TTAB and CTAB) and anionic surfactant sodium dodecyl sulfate (SDS) aqueous mixture was studied. Results show that the ATPS can be formed in every system studied and the properties of anionic aqueous twophase system（ATPSa） and cationic aqueous twophase system(ATPSc) depend upon the varieties of anionic and cationic surfactants respectively. The mixing ratio of two surfactants seems to have something to do with the micellization of richsurfactant in ATPS. The stronger the micellization of richsurfactant is, the higher the surfactant proportion in ATPS is. Experimental results also show that the matching of two surfactants chain length enlarge the region of ATPS and leads to better stability of ATPS.