Gemini表面活性剂诱导的无机介孔纳米颗粒在流体界面的自组装

The dynamic self-assembled structures can be formed at fluid interfaces by inorganic nanoparticles hydrophobilized in-situ with surfactants. Investigations on this issue are helpful to understand the interactions of nanoparticles in complex fluids and is valuable for the applications of nano self-assembly techniques in the preparation of advanced materials, mineral extraction and pharmaceutical fields. In this project, the Gemini surfactants, which have a complicated and easily tuned structure, are utilized to induce the self-assembly of mesoporous inorganic nanoparticles at fluid interfaces. Pickering emulsions and foams with specific properties are expected. By light scattering, rheology and electric microscopy techniques, the effects of Gemini surfactant structure on the in-situ hydrophobicity of inorganic mesoporous nanoparticles are explored. The relationships between the morphological elements such as the size, shape and specific areas and the self-assembled structures at fluid interfaces are recognized. The results will reveal the novel principles of interactions between surfactants and nanoparticles at fluid interfaces, and will also be beneficial for the preparation of functional Pickering emulsions and foams.

无机纳米颗粒经过表面活性剂原位疏水修饰后，可在流体界面形成具有动态性能的自组装结构。对该类结构的研究有助于深入了解复杂流体中纳米颗粒间的相互作用情况，对自组装技术在先进材料制备、矿物提炼及医药领域的应用有重要价值。本项目利用Gemini表面活性剂分子结构独特、易于调控的特点，来诱导多种形貌的介孔无机纳米颗粒在流体界面的自组装，以获得具有特殊性能的Pickering乳状液和泡沫体系。通过动态光散射、流变及电镜等技术手段，探索Gemini表面活性剂的结构对无机介孔纳米颗粒原位疏水化过程的影响，认识无机介孔纳米颗粒的大小、形状和比表面积等形貌因素与其流体界面自组装结构之间的关系。研究结果将揭示表面活性剂与纳米颗粒在流体界面相互作用及自组装的新规律，并为制备功能化的Pickering乳状液与泡沫体系奠定理论基础。

无机纳米颗粒在流体界面上的自组装及颗粒间的相互作用研究对Pickering乳液和泡沫的制备及应用具有重要意义。本项目合成了一系列阳离子Gemini表面活性剂，制备了多种形貌的介孔纳米二氧化硅颗粒；将通过阳离子表面活性剂原位疏水化修饰后的介孔纳米二氧化硅颗粒用于制备Pickering乳液和泡沫体系，并探究了Pickering乳液/泡沫性质与纳米颗粒形貌因素（比表面积、形状）、表面活性剂结构的相互关系。由介孔纳米二氧化硅协同阳离子表面活性剂共同稳定的Pickering乳液表现出独特的酸碱响应性和高耐盐性，纳米颗粒的介孔结构在其中起关键作用。由不同形状（球状、棒状、线状）的介孔纳米二氧化硅与阳离子表面活性剂协同稳定的Pickering乳液表现出不同的乳液稳定性、酸碱响应性、流变性能等。纳米颗粒形状的变化改变颗粒在界面上的排列方式及相互作用，进而对体系性质有显著影响。由Gemini表面活性剂与介孔纳米二氧化硅制备的Pickering泡沫具有优良的泡沫稳定性，对酸-碱的刺激响应性和高耐盐性。与常规表面活性剂相比，Gemini表面活性剂与纳米颗粒间具有更优的协同作用，所制备的Pickering泡沫体积更大、稳定性更好。研究结果揭示了表面活性剂与纳米颗粒在流体界面相互作用及自组装的新规律，并为制备功能化的Pickering乳状液与泡沫体系奠定理论基础。