Dye stabilised nanoemulsions as powerful platform for the synthesis of nanoparticles

通过溶胶-凝胶工艺，可以在染料稳定的纳米乳液中高精度地制备小而窄分布的二氧化硅纳米颗粒（直径约6-30 nm）。或者，根据染料的不同，可以在纳米乳液中生成非常均匀的胶囊。对这一过程的机理有一些假设，但缺乏分子水平上的详细数据。在项目开始时，应借助各种表征方法（1H-, 13C-, 29Si-NMR-，拉曼-，ir -光谱，SAXS/WAXS， TEM， SEM）和分子动力学建模来研究二氧化硅颗粒和胶囊的形成机制。SAXS/WAXS将发挥关键作用，因为在初步工作中可以获得染料分子排列以及界面处无机颗粒的结构信息。这些将被细化并与同步加速器上的时间相关测量相结合，以收集关于溶胶-凝胶过程动力学的重要数据。通过获得的信息，将这一概念扩展为一个通用平台。将对颗粒表面进行共聚和后官能化。温和的反应条件（pH约为7，无其他添加剂）也允许使用敏感的表面调节剂，如肽或蛋白质。由于在界面处的反应，期望粒子具有双面形貌。此外，核壳形态和胶体体应该可以通过这个过程获得。此外，计划用含钛单体代替二氧化硅前驱体，获得小而均匀的TiO2纳米颗粒。由于前体的水解不稳定性，可能有必要求助于非水系统。与传统的表面活性剂相比，这种染料的一个显著优点是，前者可以很容易地通过洗涤去除，而在视觉或光谱上没有问题。从系统的角度来看，该项目将着重于静态光散射实验。它们将有助于阐明纳米颗粒和-胶囊的形成机制，而无需费力的样品制备，并控制（在线）其形成过程。该项目侧重于新材料的合成，并有强有力的系统支持，以便更好地理解和控制合成。材料的选择是由应用方面做出的，但直接实现应用将超出项目的范围。该项目集中在三个关键问题上：1)染料的稳定机制；2)染料在溶胶-凝胶过程中的作用；3)将这一概念扩展到进一步的形态和材料。综上所述，该项目的通用性，灵活性和染料稳定纳米乳液作为溶胶-凝胶过程界面反应器的高潜力将得到证明。

Small, narrowly distributed silica nanoparticles (ca. 6–30 nm diameter) can be prepared with high precision in dye stabilized nanoemulsions via a sol-gel process. Alternatively, very homogeneous capsules can be generated in the nanoemulsions depending on the dyes. There are assumptions on the mechanism of the process but detailed data on a molecular level is missing. In the beginning of the project investigations on the mechanism of formation of the silica particles and capsules shall be performed with the help of various characterization methods (1H-, 13C-, 29Si-NMR-, Raman-, IR-spectroscopy, SAXS/WAXS, TEM, SEM) and modelling with molecular dynamics. SAXS/WAXS will play a pivotal role because in preliminary work structural information on the arrangement of the dye molecules as well as on the inorganic particles at the interface could be obtained. Those shall be refined and combined with time dependent measurements at the synchrotron to gather important data on the kinetics of the sol-gel process. Through the gained information, the concept shall be extended in terms of a universal platform. Copolymerizations and postfunctionalizations of the particles’ surface will be carried out. The mild reaction conditions (pH ca. 7, no further additives) shall also allow to employ sensitivesurface modificators like peptides or proteins. Because of the reaction at the interface particles with Janus morphology are expected. Furthermore, core-shell morphologies and colloidosomes should be accessible by this process. In addition, it is planned to substitute the silica precursors by titanium containing monomers to obtain small and uniform TiO2 nanoparticles. Caused by the precuorsors' hydrolytic lability there might be the necessity to fall back on non-aqueoussystems. A striking advantage of the dyes over classical surfactants is that the former can be easily removed by washing which is followed without problems visually or spectroscopically. From the methodical viewpoint, there will be a strong focus of the project on static lightscattering experiments. They shall help to elucidate the mechanism of formation of the nanoparticles and –capsules without laborious sample preparation and to control (online) the process of their formation. The project focuses on the synthesis of new materials with strong methodical support in order to better understand and control the synthesis. The selection of the materials is made by application aspects but the direct realization of applications would gobeyond the scope of the project.The project focusses on three key issues: 1) mechanism of stabilization by the dyes, 2) role of the dyes in the sol-gel process and 3) extension of the concept to further morphologies and materials.Summarizing, the project’s versatility, flexibility and high potential of dye stabilized nanoemulsions as interfacial reactors for sol-gel processes shall be demonstrated.