The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The liquid crystal structure and behavior have been alsostudied by using polarizing texture, small angle X-ray scattering, ~2H-NMR and rheometer etc. Theresult shows that when the composition of the system changes along the line of AA′ in this largeliquid crystal region, the structural change iscubic→cubic/lamellar→lamellar→larnellar/hexagonal→hexagonal. Meanwhile, we made the firstattempt of systematic study of the rheological properties of the above system. The lattice constantsof cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.
AN Ya1,2,XU Jun1,ZHANG Jin1,HU Changgang1,2,LI Ganzuo1,WANG Zhining1,WANG Zhongni1,ZHANG Xiaoyi2 & ZHENG Liqiang1 1. Key Lab of Colloid and Interface Chemistry for State Education Ministry,Jinan 250100,China
The spontaneous formation of vesicles in the aqueous of cationic surfactant phosphate (PTA) and anionic surfactant sodium dodecyl sulfate (SDS) at certain mixing ratios have obtained1. The addition of urea or NaI will expand the range of spontaneous vesicle formation. The fact is demonstrated by negative-staining transmission electron microscope(TEM) and dynamic light scattering(DLS) methods. The phenomenon especially in the part of urea is reported by us at first. Mechanism of urea/NaI–induced vesicles formation is discussed from the viewpoint of the molecular geometry packing parameter f, conformation and interaction.
Spontaneous vesicle formation and transforma- tion of vesicle to tubular microstructure have been observed in aqueous mixtures of tri-(n-dodecyl-dimethyl-hydroxy- propylammonium chloride) phosphate (PTA) and sodium dedecyl sulfate (SDS), which is supported by negative-stain- ing transmission electron microscopy (TEM), scan electron microscopy (SEM) and dynamic light scattering (DLS). Spherical vesicles aggregate to tubular microstructures with their diameters and lengths respectively of about 100 and 7000 nm in the freshly prepared sample at the molar ratio of PTA/SDS=3/7 and a total surfactant concentration of 0.01 mol/L. The diameter, the length and the quantity of tubular structures all increase with the increase of the total concen- tration of surfactant and the sample aging.
