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SiO2纳米颗粒与聚氧乙烯对Pickering乳液的协同稳定作用
引用本文:谭伟强,臧渡洋,李云飞,张永建,陆晨君,栗志广.SiO2纳米颗粒与聚氧乙烯对Pickering乳液的协同稳定作用[J].高等学校化学学报,2014,35(1):85-91.
作者姓名:谭伟强  臧渡洋  李云飞  张永建  陆晨君  栗志广
作者单位:1. 空间应用物理与化学教育部重点实验室, 西北工业大学理学院, 西安 710129;
2. 凝固技术国家重点实验室, 西北工业大学材料学院, 西安 710072
基金项目:国家自然科学基金(批准号:51301139);陕西省自然科学基金(批准号:2012JQ1016)和西北工业大学基础研究基金(批准号:JCY20130147)资助.
摘    要:研究了聚氧乙烯(PEO)与SiO2纳米颗粒对水/二甲苯体系Pickering乳液的协同稳定作用. 实验发现,PEO的存在减小了乳液液滴的平均直径,抑制了乳液的相反转,有效阻止了乳液的熟化,使乳液具有更好的稳定性. 进一步对纳米颗粒膜的流变性质进行研究,结果表明,PEO高分子促进了纳米颗粒形成更大尺寸的聚集结构,提高了其在界面上的吸附性,增强了颗粒膜的力学性能,在较小颗粒用量条件下使得Gibbs稳定性判据得到满足.

关 键 词:Pickering乳液  SiO2纳米颗粒  界面张力  反相  聚氧乙烯
收稿时间:2013-09-16

Stability Mechanisms of Pickering Emulsion Co-stabilized by Silica Nanoparticles and PEO
TAN Weiqiang,ZANG Duyang,LI Yunfei,ZHANG Yongjian,LU Chenjun,LI Zhiguang.Stability Mechanisms of Pickering Emulsion Co-stabilized by Silica Nanoparticles and PEO[J].Chemical Research In Chinese Universities,2014,35(1):85-91.
Authors:TAN Weiqiang  ZANG Duyang  LI Yunfei  ZHANG Yongjian  LU Chenjun  LI Zhiguang
Institution:1. Key Laboratory of Space Applied Physics and Chemistry of Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an 710129, China;
2. State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China
Abstract:The Pickering emulsions with 65% water and 35% xylene system stabilized by silica nanoparticles or by both the particles and polyethylene oxide(PEO) additives were prepared. The emulsification was performed using a rotor-stator homogenizer under varied rotation speeds from 5000 r/min to 24000 r/min. The emulsion droplets were observed using an optical microscope, consequently, the droplet diameters vs. rotation speed and aging time were obtained. For most cases, W/O type emulsion was obtained. It is found that the mean diameter of water droplets decreases with increasing shear rate or shear duration. With the presence of PEO, the diameters of the droplets are significantly reduced and the phase inversion from W/O to W/O/W is prevented, which occurs in the system without PEO when prolong the shear duration. In addition, the coalescence of droplets is completely inhibited. To elucidate the ultrastability of the Pickering emulsion resulted from co-stabilization by silica nanoparticles and PEO, we study the rheological properties of the particle layers at the gas-liquid interface using the Langmuir trough equipped with a Wilhelmy plate. The silica nanoparticles were spreaded on the surface of either water or PEO water solution, consequently and the effect of PEO additives on particle layer properties was investigated. The results confirm that PEO additives can favor the trapping of particles at the water/xylene interface, due to the formation of larger size aggregates with the presence of PEO. Therefore, the particle layer has a higher compression modulus. The stronger mechanical property of the particle layer protects the water/xylene interface from rupture when exerted turbulent shearing, hence preventing the occurrence of phase inversion from W/O emulsion to the W/O/W one. Owing to the satisfaction of the Gibbs stability criterion, the coalescence of droplets is almost completely inhibited. The results demonstrate that the rheological properties of the liquid/liquid interface play an important role in the stability of Pickering emulsion.
Keywords:Pickering emulsion  SiO2 nanoparticles" target="_blank">2 nanoparticles')" href="#">SiO2 nanoparticles  Interfacial tension  Phase inversion  Polythylene oxide(PEO)
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