Control of structure and stability of vesicular systems by means of amphiphilic copolymers and their fixation

囊泡是非常重要的胶体体系，对其结构、性质和稳定性的控制对其潜在的应用至关重要。由于它们通常是亚稳态系统，因此可以选择在形成过程中通过添加剂的存在来操纵囊泡的性质，从而获得动力学控制的产品。在这个项目中，我们将特别考虑两亲性共聚物对自发形成表面活性剂泡囊的影响，目的是通过添加聚合物的类型和数量以及随后这些动力学控制系统的固定来控制结构和性能。模型体系的前期工作表明，强协同作用的表面活性剂混合物通过盘状中间体形成囊泡。相应地，可以通过添加共聚物来稳定该中间结构。通过这样做，可以控制囊泡的大小和多分散性，并且这些聚合物修饰的囊泡在老化过程中也更加稳定。在这个项目中，这些关于通过两亲共聚物控制尺寸、多分散性和稳定性的非常有趣的结果将被推广，并建立在坚实和广泛的基础上。为此，将研究与应用相关的表面活性剂混合物对共聚物添加的影响。。这将产生一系列相关的共聚物/表面活性剂混合物，用于稳定的囊泡系统，其中共聚物在这里起到一种‘胶体催化剂’的作用，改变了囊泡形成的途径。由于动力学控制，这一过程产生了非常单分散的体系，由于共聚物的存在，这些体系的寿命相对较长。应使用该时间窗口来化学固定这些明确定义的结构，从而产生永久稳定的结构。这应首先通过有机单体的聚合来完成，或者通过使用无机前驱体来完成，在无机前驱体中通过水解形成无机骨架。这种固定的囊泡系统不仅因为它们的长期稳定性，而且还因为它们的渗透性，因此活性物质的释放可以通过固定的类型和程度来控制。固定囊泡的渗透性和机械性能将被表征，以便能够产生这些永久中空纳米结构的定制特性。总体而言，该项目将以受控方式生产具有所需特性和功能的囊泡和囊泡杂交系统，因为它们对各种应用具有很高的兴趣。

Vesicles are very important colloidal systems, where the control of structure, properties and stability are of central importance for their potential applications. As they are often metastable systems, there is the option to manipulate vesicle properties by the presence of additives during the formation process and thereby to obtain kinetically controlled products. In this project we will in particular consider the effect of amphiphilic copolymers on spontaneously forming surfactant vesicles, with the aim of controlling structure and properties by the type and amount of added polymer and the subsequent fixation of these kinetically controlled systems. Pre-work on a model system has shown, that strongly synergistic surfactant mixtures form vesicles via a disk-like intermediate. Correspondingly this intermediate structure can be stabilized by the addition of a copolymer. By doing so the size and polydispersity of the vesicles can be controlled and these polymermodified vesicles are also much more stable against ageing processes. In this project these very interesting results regarding control of size, polydispersity and stability by means of amphiphilic copolymers shall become generalized and be put on a solid and broad basis. For this purposes surfactant mixtures relevant for applications will be investigated with respect to the effect of copolymer addition. . This will yield a comprehensive spectrum of relevant copolymer/surfactant mixtures for stable vesicle systems, where the copolymer functions here as a kind of 'colloidal catalyst', that modifies the pathway of vesicle formation. Due to the kinetic control this process yields very monodisperse systems, which are relatively long-lived due to the presence of the copolymer. This time window shall be used in order to chemically fix these well-defined structures and thereby create permanently stable structures. This shall be done in first by polymerization of organic monomers, and alternatively by using inorganic precursors, where by hydrolysis an inorganic framework is formed. Such fixed vesicle systems are not only interesting due to their long-time stability but also as e. g. their permeability and therefore the release of active agents can be controlled by type and extent of the fixation. The permeability and the mechanical properties of the fixed vesicles will become characterized, in order to be able to generate tailor-made properties of these permanent hollow nanostructures. In general, this project will produce in a controlled fashion vesicles and vesicle hybrid systems with desired properties and functionality, as they are of high interest for a variety of applications.