Cloud point property was found in the aqueous mixtures of sodium dodecyl sulfate（SDS）and cetyl trimethyl ammonium bromide（CTAB）and the cloud point area in pseudo ternary plase diagram of SDS/CTAB/Na2SO4/H2O was studied.It was found that the cloud point area was the aqueous two-phase system area,in which the containing of SDS was more than that of CTAB.The cloud point area would enlarge when the temperature was high and the length of cationic surfactant carbochain had some effect on the position of cloud point area.
The state of aromatic micromolecule in cationic-anionic surfactant mixtures was investigated by the determination of distribution ratio of sodium benzoate and phenylaetic acid in them,respectively.As a result,the non-bar structures of benzoic ion and pheylacetic ion made them scarely be able to pentrarte into organized aggregations.Benzoic ions are mostly attracted by the organized aggregations positively charged,so they existed mainly in couterion layer.While phenylacetic ion,because of its steric effect,had a weak attraction to organized aggregations positively charged,which is weaker than the acting forces of hydrogen bond among pheylacetic acid molecules.So phenylacetic acid molecules did not exist in couterion layer,but it existed as hydrogen-bond form mainly.
