超低浓度离子型表面活性剂/相同电荷纳米颗粒协同稳定的新型乳状液及其稳定机制

Emulsions are extensively applied in fields of high technology, industrial and agricultural productions, as well as peoples’ daily life, and the relative technical advances are therefore always attractive. The traditional emulsions are dynamically stabilized by surfactant films adsorbed at oil/water interface, whereas the Pickering emulsions are almost thermodynamically stabilized by amphiphilic colloid particles adsorbed at oil/water interface which form a solid obstacle to prevent flocculation and coalescence of oil droplets, normally difficult to demulsify. This project try to construct novel emulsions stabilized by extremely low concentration of ionic surfactants (0.001~0.1cmc) in combination with very low concentration of inorganic nanoparticles (0.0001~0.1 wt.%) both are similarly charged in aqueous media. The emulsion not only has good stability and fluidity, but also can be demulsified quickly. This project try to explore relative stabilization mechanisms and to establish a new emulsion stabilization theory by systematically studying and examining the electrostatic repulsions/electrical double layer repulsions in the systems, the composition, structure and properties of the lamellae between droplets, as well as by constructing smart systems capable of realizing quick demulsification and re-stabilization cycles. Due to saving large amount of emulsifies and preventing their ultimate discharge into environments, this project is therefore not only scientifically significant but also may bring significant economic and environmental benefits to relative application fields.

乳状液在高新技术、工农业和日常生活等领域有广泛的应用，因而相关技术进步引人关注。传统乳状液由表面活性剂吸附膜保持动态稳定，属于热力学不稳定体系；Pickering乳状液由双亲性颗粒吸附在油/水界面阻碍液珠聚结而接近热力学稳定，但破乳相对困难。本项目利用超低浓度离子型表面活性剂(0.001~0.1cmc)和相同电荷的无机纳米颗粒(0.0001~0.1wt.%)构建一种新型乳状液，该乳状液不仅具有良好的稳定性和流动性，还能够快速破乳。通过系统考察体系中静电/双电层的排斥作用、表面活性剂/颗粒的吸附和分散、连续相液膜的组成、结构和性质及其对液珠絮凝和聚结的阻碍作用，以及能实现快速破乳和再稳定循环的智能体系的构建，探索和阐述新型乳状液的稳定机制，建立新的乳状液稳定理论。由于新型乳状液大幅度降低了乳化剂的用量和排放，因此本项目研究不仅具有重要的科学意义，而且将给相关应用行业带来重大的经济和环境效应。

随着纳米科学技术的迅速发展，表面活性剂协同纳米颗粒稳定流体分散体系得到广泛的研究，二者之间的相互作用及其界面自组装逐渐成为研究热点。本项目利用超低浓度离子型表面活性剂(0.001~0.1cmc)和相同电荷的无机纳米颗粒(0.0001~0.1wt.%)构建一种新型oil-in-dispersion乳状液，该乳状液不仅具有良好的稳定性和流动性，还能够快速破乳，相关的稳定机理难以用经典的DLVO理论、位阻稳定理论和Pickering稳定理论来解释。通过系统考察体系中静电/双电层的排斥作用、表面活性剂/颗粒的吸附和分散、连续相液膜的组成、结构和性质及其对液珠絮凝和聚结的阻碍作用，以及能实现快速破乳和再稳定循环的智能体系的构建，探索和阐述了该乳状液的稳定机制，丰富了乳状液稳定理论，在Angew. Chem.等期刊发表27篇标注论文。本项目研究不仅具有重要的科学意义，而且将给相关应用行业带来重大的经济和环境效应。