Synthesis of monodisperse, highly ordered polymer foams via milli- and microfluidic techniques

聚合物泡沫在诸如包装、绝缘或冲击保护的不同领域中具有巨大的商业利益。根据其应用，聚合物泡沫必须满足特定的要求，这些要求可以通过组成和结构来定制。在这个项目中，我们希望研究结构-性质关系。为了确定泡沫结构，需要确定许多细节，例如孔径、孔数、孔径分布和孔连通性。然而，传统制造工艺的高度复杂性使得控制材料的结构和性能变得非常困难，通常甚至是不可能的。即使允许改变泡沫结构的方法也不允许制造单分散和高度有序的聚合物泡沫。所有可商购的泡沫具有宽的尺寸分布，这意味着性能只是相应分布的平均值。最重要的是对结构的精确控制，这将使我们能够定制聚合物泡沫的性能。为了实现这一目标，需要找到新的概念。拟议的项目旨在发展这样一个新的概念。重点将放在聚苯乙烯泡沫塑料上，但要记住，长期目标是将这一概念转移到各种聚合物泡沫塑料上。该概念基于分别通过微流体技术和微流体技术产生的单分散、高度有序的液体泡沫和乳液的聚合。其基本思想是通过易于制作的模板制造所需的材料。在一种情况下，这将是具有高苯乙烯含量的水包苯乙烯乳液，我们将通过流体技术发泡。发泡乳液的随后聚合旨在产生孔径对应于模板泡沫的气泡尺寸的聚苯乙烯泡沫。在第二种情况下，我们将产生苯乙烯包水乳液，其将直接聚合。聚合物泡沫预期具有对应于模板乳液的水滴尺寸的孔径。在这两种情况下，氧化还原引发剂将用于开始自由基聚合。一旦概念确立，我们将开发一种具有明确定义的孔径梯度的聚合物泡沫。最后但并非最不重要的是，需要测量所得聚合物泡沫的机械性能。为了量化结构和性能之间的关系，我们将比较（a）不同孔径和连通性的单分散聚合物泡沫，（B）没有和具有孔径梯度的单分散聚合物泡沫，和（c）单分散与多分散聚合物泡沫。

Polymer foams are of great commercial interest in such diverse fields as packaging, insulation or impact protection. Depending on its application a polymer foam has to meet specific requirements which can be tailored via the composition and the structure. In the proposed project we would like to study structure-property relationships. To characterise the foam structure a number of details such as pore size, number of pores, pore size distribution and pore connectivity need to be determined. However, the high complexity of traditional manufacturing processes makes it very difficult, often even impossible, to control the structure and thus the properties of the material. Even processes which allow changing the structure of the foam do not allow manufacturing monodisperse and highly ordered polymer foams. All commercially available foams have a broad size distribution, which means that the properties are just the mean of the respective distribution. It is above all the precise control of the structure which will enable us to tailor the properties of polymer foams. To reach this goal new concepts need to be found.The proposed project aims at developing such a new concept. The focus will be on polystyrene foams, keeping in mind, however, that the long-term aim is to transfer this concept to a broad variety of polymer foams. The concept is based on the polymerisation of monodisperse, highly ordered liquid foams and emulsions which are generated via milli- and microfluidic techniques, respectively. The basic idea is to manufacture the desired materials via templates which are easy to make. In one case this will be a styrene-in-water emulsion with a high styrene content which we will foam via the fluidic technique. The subsequent polymerisation of the foamed emulsion is intended to lead to a polystyrene foam whose pore size corresponds to the bubble size of the templating foam. In the second case we will generate a water-in-styrene emulsion which will directly be polymerized. The polymer foam is expected to have pore sizes which correspond to the water droplet size of the templating emulsion. In both cases a redox-initiator will be used to start the radical polymerisation. Once the concept is established, we will develop a route towards a polymer foam with a clearly defined pore size gradient. Last but not least, the mechanical properties of the resulting polymer foams need to be measured. In order to quantify the relation between structure and properties we will compare (a) monodisperse polymer foams of different pore sizes and connectivities, (b) monodisperse polymer foams without and with a pore size gradient, and (c) monodisperse with polydisperse polymer foams.