TiO_2-SA-Arg纳米颗粒稳定Pickering乳液的制备及稳定因素

Fabrication and Factors of Stabilization of Pickering Emulsion Based on TiO_2-SA-Arg Nanoparticles

采用浸渍改性法将水杨酸（SA）与精氨酸（Arg）修饰到纳米TiO2颗粒表面,并采用红外光谱、X射线衍射、比表面积分析仪、透射电镜、动态光散射、热重分析以及接触角测定仪对改性粒子的结构及性能进行了表征。结果显示,改性颗粒为介孔混晶结构的片状纳米粒子,颗粒较未改性前表面亲水性减弱且在水中团聚减轻。研究了乳化时间、水相pH值与电解质、固体粒子用量、油相体积分数、静置温度对改性粒子稳定的硝基苯/水型Pickering乳液的静置稳定性的影响。结果表明,水相pH=3-5时和Na Cl浓度为0.05-0.2 mol/L时,乳液静置稳定性最佳;乳液乳化系数与固体粒子用量呈成正比关系;观测到乳液在油相体积分数为40%发生转相。测定了固体颗粒的临界胶束浓度（CMC）值,发现改性颗粒具有类似双亲性高分子的性质。

Salicylate （SA） and arginine （Arg） were modified on the surface of nano TiO2 by impregnation method, FT-IR, XRD, BET, TEM, dynamic light scattering（DLS）, TG and contact angle measurement were employed to characterized the structures and properties of the modified particles. The results show that the modified particles are sheet mesoporous nanoparticles with mixed crystal structure. The particles have weakening hydrophilic surface and less reunion in water compared with the unmodified particles. The effect of emulsification time, the pH value and the electrolyte concentration of the aqueous phase, the amount of solid particles, the oil phase volume fraction and standing temperature on structure and stability of nitrobenzene/water emulsion of Pickering emulsion was studied. The results show that, the emulsion has the best stand stability when the pH value of aqueous phase is 3--5 or the electrolyte concentration is 0.05--0.2 mol/L; the creaming index of emulsion is increased with the solid particle concentration increasing; the phase inversion occurs when the oil phase volume fraction is 40 %. The critical micelle concentration of solid particles （CMC） value was determined and the result shows that modified particles have similar amphiphilic properties of polymer.