摘要
A metal-ligand coordinated surfactant system formed by calcium dodecylsulfate(Ca(DS)2)/tetradecyldimethylamine oxide (C14DMAO)/H2O was studied in terms of surface tension,conductivity,negative-staining TEM,phase behavior and rheological operation.In C14DMAO solution,when Ca(DS)2 is added,metal-ligand complexes form between the Ca 2+and N→O group of C14DMAO.Under this metal-ligand driving force,different phases can be obtained at different concentrations and different ratios of Ca(DS)2 and C14DMAO.At the fixed C14DMAO concentration,L1-phase consisting of spherical micelles forms at first.With the addition of Ca(DS)2,the spherical micelles elongate to be wormlike micelles and then after an L1/L-two phase region,the birefringent vesicle-phase(Lv-phase)region is observed.When Ca(DS)2 concentration continues to increase,a gel-phase region is found after the Lv-phase region and then precipitates of undissolved Ca(DS)2 appear.The transition between different phases is affected by temperature remarkably.The wormlike micellar solutions and vesicle solutions were checked by rheological measurements and showed apparent viscoelasticity at high surfactant concentrations.
A metal-ligand coordinated surfactant system formed by calcium dodecylsulfate（Ca（DS）2）/tetradecyldimethylamine oxide （C14DMAO）/H2O was studied in terms of surface tension,conductivity,negative-staining TEM,phase behavior and rheological operation.In C14DMAO solution,when Ca（DS）2 is added,metal-ligand complexes form between the Ca 2＋and N→O group of C14DMAO.Under this metal-ligand driving force,different phases can be obtained at different concentrations and different ratios of Ca（DS）2 and C14DMAO.At the fixed C14DMAO concentration,L1-phase consisting of spherical micelles forms at first.With the addition of Ca（DS）2,the spherical micelles elongate to be wormlike micelles and then after an L1/L-two phase region,the birefringent vesicle-phase（Lv-phase）region is observed.When Ca（DS）2 concentration continues to increase,a gel-phase region is found after the Lv-phase region and then precipitates of undissolved Ca（DS）2 appear.The transition between different phases is affected by temperature remarkably.The wormlike micellar solutions and vesicle solutions were checked by rheological measurements and showed apparent viscoelasticity at high surfactant concentrations.
基金
supported by the National Natural Science Foundation of China (20833010 and 20803045)
the Foundation of Ministry of Education of China for New Teachers (200804221008)
