高等学校化学学报 ›› 2014, Vol. 35 ›› Issue (1): 85.doi: 10.7503/cjcu20130905

• 物理化学 • 上一篇    下一篇

SiO2纳米颗粒与聚氧乙烯对Pickering乳液的协同稳定作用

谭伟强1, 臧渡洋1(), 李云飞1, 张永建2, 陆晨君1, 栗志广1   

  1. 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
  • 收稿日期:2013-09-16 出版日期:2014-01-10 发布日期:2013-12-09
  • 作者简介:联系人简介: 臧渡洋, 男, 博士, 讲师, 主要从事功能软物质的研究。E-mail:dyzang@nwpu.edu.cn
  • 基金资助:
    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

Stability Mechanisms of Pickering Emulsion Co-stabilized by Silica Nanoparticles and PEO

TAN Weiqiang1, ZANG Duyang1,*(), LI Yunfei1, ZHANG Yongjian2, LU Chenjun1, LI Zhiguang1   

  1. 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
  • Received:2013-09-16 Online:2014-01-10 Published:2013-12-09
  • Contact: ZANG Duyang E-mail:dyzang@nwpu.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(No.51301139), the Shaanxi Provincial Natural Science Foundation, China(No.2012JQ1016) and the Northwestern Polytechnical University Foundation for Fundamental Research, China(No.JCY20130147)

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

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.

Key words: Pickering emulsion, SiO2 nanoparticles, Interfacial tension, Phase inversion, Polythylene oxide(PEO)

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