疏水纳米氧化硅稳定水包油乳液机制研究

Mechanism study of hydrophobic nano-silica stabilizing oil-in-water emulsion

以矿物油、表面活性剂、疏水纳米SiO_(2)为原料,采用机械乳化法制备了含纳米SiO_(2)水包油型乳液。通过响应曲面实验得出SiO_(2)含量是影响乳液稳定性的主要因素,并在此基础上系统地研究了疏水纳米SiO_(2)对乳液稳定性及特性的影响。结果表明:当固体颗粒含量达到一定时,才能形成稳定的乳液,其形状与大小随着颗粒含量的增加而发生改变;与传统乳液相比,含固体颗粒乳液具有更好的热稳定性。其次,采用荧光显微镜、界面张力、界面流变等测试手段揭示了疏水颗粒稳定水包油型乳液的相应机制。结果表明:疏水纳米SiO_(2)吸附于油水界面改变了界面膜强度与结构,并与表活剂产生协同作用降低了油水界面张力,从而使乳液更加稳定。

Mechanical emulsification was used to prepare an oil-in-water emulsion containing nano-SiO_(2)using mineral oil,surfactant,and hydrophobic nano-SiO_(2)as raw materials.By response surface experiments,the emulsion stability much depends on the nano-SiO_(2)content.On this basis,the effect of hydrophobic nano-SiO_(2) on emulsion stability and properties was thoroughly investigated.The results showed that a stable emulsion could be formed only when the content of solid particles reached a certain level,and the droplet shape and size changed with the increase of nano-SiO_(2)content.Comparing with conventional emulsion,emulsion with solid SiO_(2)particles exhibited greater thermal stability.Additionally,the corresponding mechanism of hydrophobic particles stabilizing oil-in-water emulsion was revealed with the help of a fluorescence microscope,interfacial tension,interfacial rheology,and other structure characterization methods.The results indicated that hydrophobic nano-SiO_(2)adsorbed on the oil-water interface changed the strength and structure of the interfacial film,and synergized with surface activator to remarkably reduce the interfacial tension between oil and water,thus making the emulsion more stable.