The cloud points (CP) of aqueous solutions of two ethylene oxide–propylene oxide–ethylene oxide tri-block copolymers (EO)10(PO)16(EO)10 and (EO)1(PO)17(EO)1 were measured in the presence of additives, such as salts, alkalis, acids, polymer and ionic surfactant. The results obtained in this study indicated that salts decrease the CP of the two tri-block copolymers in the order of NaCl>CaCl2>MgCl2 and Na3PO4>Na2SO4>NaCl. Alkalis caused a sharp drop of CP of the two tri-block copolymers. Acids increased the CP. Water soluble polymer such as polyvinylpyrrolidone (PVP), hydrolysis polyacrylamide (HPAM) and cation-polyacryamide (cation-PAM) decreased the CP. Ionic surfactants such as sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) increased the CP. The extent of lowering depends on the structure and concentration of additives and the number of ethylene oxide group of tri-block copolymers.

Vesicles can be formed spontaneously in aqueous solution of a single anionic surfactant sodium dodecyl benzenesulfonate (SDBS) just under the inducement of salt, which makes the formation of vesicle much easier and simpler. The existence of vesicles was demonstrated by TEM image using the negative-staining method. The mechanism of the formation may be attributed to the compression of salt on the electric bilayer of the surfactant headgroups, which alters the packing parameter of the surfactant. The addition of the zwitterionic surfactant lauryl sulfonate betaine (LSB) makes the vesicles more stable, expands the range of formation and vesicle size, and reduces the polydispersity of the vesicles. The vesicle region was presented in a pseudoternary diagram of SDBS/LSB/brine. The variations of vesicle size with the salinity and mixing ratios, as well as the surfactant concentration, were determined using the dynamic light scattering method. It is found that the vesicle size is independent of the surfactant concentration but subject to the salinity and the mixing ratio of the two surfactants.

The chemical composition, morphology of the particles of positively charged layered double hydroxides (LDHs) were studied by ICP, Mastersizer, TEM. The preliminary results indicated that with adding LDHs to 1% laponite dispersion the yield stress of laponite/LDHs mixed dispersions increased at first, then decreased dramatically to a minimum, and the yield stress rose again when LDHs increased further.

The intercalation reaction of polyoxyethylene sulfate (PEGS) withMg-Al-nitrate [Mg-Al-NO3] layered double hydroxide (LDH)wasinvestigated by using X-ray diffraction, infrared spectroscopy, and transmission electron microscopy (TEM). X-ray diffractograms showed that the basal spacing of the [Mg-Al-NO3]LDH with PEGS as the intergallery anion expanded from 0.89 to 2.37nm to form [Mg-Al-(PEGS)], but no expansion of the basal spacing was observed when poly(ethylene glycol) (PEG) reacted with [Mg-Al-NO3]. The characteristic absorption bands of the organic anion in the infrared spectra were obtained after prolonged treatment with deionized water, demonstrating the stability of the intercalation compounds. Furthermore, TEM analysis revealed that [Mg-Al-NO3], which consisted of hexagonal particles approximately 100-120nm in length, changed into monodisperse rigid spheres approximately 200 nm in diameter after the intercalation of PEGS.

The lamellar phase in colloidal suspensions of positively charged platelets of layered double hydroxides (LDHs) was studied with synchrotron small angle X-ray scattering and optical observations.