Schaltbare Mikrogele an Öl-Wasser Grenzflächen

采用pH和温度敏感性微凝胶制备刺激敏感性乳液。在这个项目中，我们调查的界面活性的聚（N-异丙基丙烯酰胺（PNiPAM）为基础的微凝胶和与这些微凝胶稳定的乳液的性质，以了解乳液稳定的机制。特别是微凝胶覆盖界面的粘弹性特性的相关性以及微凝胶电荷的影响进行了研究。为此目的，改变几个参数，例如，采用微凝胶的共聚单体组成和结构、油的类型、体积分数和乳化程序对乳液稳定性的影响以及几种不同的实验技术。界面张力和界面机械性能与乳液的热响应和pH响应的相关性通过界面流变学检查，并且通过冷冻馏分低温扫描电子显微镜（Cryo-SEM）检测界面处的可切换微凝胶的胶体超结构。利用微流控装置研究了系统参数对受控碰撞后液滴聚并过程的影响。

Stimuli-sensitive emulsions are prepared employing pH and temperature sensitive microgels. In this project we investigate the interfacial activity of poly (N-isopropylacrylamide (PNiPAM) based microgels and properties of the emulsions stabilized with these microgels in order to understand the mechanism of emulsion stabilization. In particular the relevance of viscoelastic properties of the microgel covered interface as well as the influence of microgel charges are examined. For this purpose several parameters are varied as, e.g., the comonomer composition and architecture of the microgels, the type of oil, the volume fraction and the emulsification procedure on the emulsion stability and several different experimental techniques are employed. The correlation of interfacial tension and interfacial mechanical properties with the thermo- and pH- responses of the emulsions are examined by interfacial rheometry and the colloidal suprastructures of the switchable microgels at the interface are detected by freeze-fraction cryogenic scanning electron microscopy (Cryo-SEM). Micro-fluidic devices are used to visualize the influence of system parameters on the process of droplet coalescence after controlled collision.