Metallopolymers as multifunctional and multistimuli-responsive shape-memory materials

形状记忆聚合物能够在变形后恢复其原始形状。一旦外部触发(例如加热)，聚合物将从临时形状返回到其初始形状。金属聚合物是设计新型形状记忆聚合物的合适候选者，可以被认为是现有形状记忆聚合物和形状记忆合金之间缺失的一环。形状记忆金属聚合物是一种可按需切换的形状记忆聚合物。由于集成的超分子相互作用(即金属-配体-相互作用)，可逆性(从低到高)以及合适的触发(例如，温度、化学物质和氧化还原反应)都可以调节。在该项目中，将制备具有不同金属离子(即不同潜在触发剂)和共聚单体的新金属聚合物网络。在这方面，将使用两种不同的处理方法，即反应性喷墨打印以及批量共聚。将研究产生的金属聚合物的形状记忆行为，以及在不同的外部刺激下触发材料的可能性，如热、光或化学物质。此外，还将详细研究所选择的金属盐对所产生的性质的影响以及不同刺激的寻址能力。这些基本信息稍后将用于新型三重形状记忆金属聚合物的设计。为此，需要两种不同类型的金属络合物，它们可以彼此独立地触发。因此，可以触发一个金属络合物以获得从第一临时形状到另一临时形状的转变。最后，在其他条件下(例如，较高温度)通过相同的刺激或通过利用完全不同的刺激(例如，热和光)来处理另一金属络合物，从而形成最终的永久形状。在该项目的另一部分中，将研究形状记忆金属聚合物的自愈合能力。在此背景下，将研究形状记忆行为对自修复行为的影响，并将其与经典的自修复金属聚合物进行比较。因此，人们将研究是否存在形状记忆辅助的自愈(SMASH)。最后，研究了一种全新的形状记忆行为，即多路三重形状记忆行为。为此，需要一种具有两个可独立寻址的金属络合物的金属聚合物。此外，必须利用两种不同的刺激。与经典的三重形状记忆聚合物相比，这种新的行为提供了在施加第一个外部刺激后有两个不同的临时形状的可能性，这取决于所用刺激的顺序。因此，如果先施加光线，就会得到完全不同的形状。最后，如果另一种刺激也被使用，则将获得永久形状。

Shape-memory polymers are able to recover their original shape after preceded deformation. Upon an external trigger (e.g., heat) the polymer will return from the temporary shape into its initial shape. Metallopolymers are suitable candidates for the design of novel shape-memory polymers, which can be considered as the missing link between the established shape-memory polymers and shape memory alloys. Shape-memory metallopolymers are on-demand switchable shape-memory polymers. Due to the integrated supramolecular interaction (i.e. the metal-ligand-interaction) the reversibility (from low to high) as well as the suitable trigger (e.g., temperature, chemicals and redox reactions) can be tuned. Within the project, new metallopolymer networks with different metal ions (i.e. different potential triggers) and comonomers will be prepared. Within this context, two different processing methods will be utilized, i.e. reactive inkjet printing as well as copolymerization in bulk. The resulting metallopolymers will be investigated regarding their shape-memory behavior and the possibility to trigger the materials with different external stimuli like heat, light or chemicals. Furthermore, the influence of the chosen metal salt on the resulting properties as well as the addressability by the different stimuli will be studied in detail. This basic information will later be utilized for the design of novel triple-shape memory metallopolymers. For this purpose, two different types of metal complexes are required, which can be triggered independently from each other. Thus, one metal complex can be triggered to obtain a transition from the first temporary shape to the other one. Finally, the other metal complex will be addressed by the same stimulus at other conditions (e.g., higher temperature) or by the utilization of a complete different stimulus (e.g., heat and light) resulting in the final permanent shape. In another part of the project the self-healing ability of the shape-memory metallopolymers will be studied. In this context, the influence of the shape-memory behavior on the self-healing behavior will be studied and will also be compared to the classical self-healing metallopolymers. Thus, it will be investigated if there is a shape-memory assisted self-healing (SMASH). Finally, a completely new shape-memory behavior will be studied, which is the multiway triple shape-memory behavior. For this purpose, a metallopolymer with two independently addressable metal complexes is required. Furthermore, two different stimuli have to be utilized. In contrast to classical triple shape-memory polymers this new behavior offers the possibility to have two different temporary shapes after the applying of the first external stimulus depending on the order of the utilized stimulus. Thus, if light is applied first a completely different shape will be obtained. Finally, if the other stimulus is also used the permanent shape will be obtained.