Rheological Properties And Applications Of PH-responsive Wormlike Micelles Formed By Sodium Oleate

With the in-depth research in the field of surfactant, intelligent worm-like micelles system attracts more and more attention,which becomes a research hotspot. intelligent worm-like micelles system that could take stimulate response behavior responding to the environmental changes is widely used in oil field, food, cosmetics, drug delivery.etc. This article mainly studied the sodium oleate worm-like micelles’ stimulate response behavior of pH by the method of rheology when added different organic cationic salts. It also studied the type of pH-response worm-like micelles’ applications in drug solubilization, pesticide photodegradation suppression, as well as the template for the preparation of nano-silica particles.Rheological steady shear and dynamic viscoelastic experiment confirmed the behavior of formation of the micelles induced by three kinds of organic cationic salts(triethylamine hydrochloride salt, triethanolamine hydrochloride, benzyl trimethyl ammonium bromide), respectively. In the steady shear experiment, changing the pH value of solution could appeare shearing dilution in a certain range. Dynamic viscoelastic experimental results met the Cox-Merz rules and Cole-Cole figure fitted approximate semicircle, which instructed the micelles system was in line with the Maxwell model and the solution confirmed the vermicular micellar system. The viscosity of NaOA/organic cationic salts solutions show the characteristic of that first decrease and then increase with the changing of pH value. At its maximum viscosity, system is to be cloudy by decreasing pH value. For each system, it is a transparent solution with low viscosity at high pH value. The mechanism of the three kinds of pH-response micellar system is that the ionization potential of counter ions will change with the changing of pH value of the solution, which makes the electric properties of sodium oleate head base change, causing the micelle structure change. The difference of pH-response of three kinds of system is mainly due to the substructure of organic cationic salts. BTAB owns a higher space steric hindrance with a benzene ring, so its viscoelastic is minimal. Et3NHC1is similar to TEA·HC1in structure, but its space steric hindrance is bigger than Et3NHC1owing to the-OH groups, thus viscoelastic of TEA·HC1system is lower than Et:,NHC1system.Further we studied the effect of NaOA/Et3NHC1worm-like micelles on avermectin B2solubilization, pesticide photodegradation suppression at different pH value. Ultraviolet spectrophotometer and high performance liquid chromatography (HPLC) were used to measure the content of abamectin B2. Results showed that abamectin B2exsited a higher solubility in NaOA/Et3NHCl system, but results of pH-control showed that the formnation of the worm-like micelles was not conducive to the dissolution of avermectin B2. Meanwhile we prepared mesoporous silica particles using NaOA/BTAB worm-like micelles system as templates, and used transmission electron microscopy (SEM), polycrystalline X-ray diffraction and laser particle size instrument to characterize the mesoporous silica particles. Results showed that we got nanometer level, appearance with orderly worm-like hole spherical silica particles.