Push, Push, Push – Cooperative Actuators and Actuators Fields by Direct Writing Pro-cesses

基于C，H插入反应的双光子交联（2PC）可以通过无掩膜直接写入工艺从磁性复合材料中生成微致动器。这种共聚物采用双光子发色团，如适当取代的蒽醌基团，并借助于双光子过程交联。这种交联过程发生在聚合物的玻璃状状态下。书写过程完成后，所有非交联聚合物分子被冲洗出来，形成微观结构。如果在预聚物层沉积之前，将纳米颗粒混合到预聚物中，则可以一步直接获得三维微结构纳米复合材料。因此，在这种无掩模书写过程的帮助下，几乎任何形式的磁致动微结构都可以进行三维书写，并且可以自我支撑。在该项目中，将产生协同磁致动结构，如微混合器或微泵的纤毛表面或致动器场，这些结构将显示出超向波。通过改变所写结构，可以生成具有设计特性的致动器场或能协同行动的致动器场。更大的结构可以通过相同的聚合物成型，但通过传统的光化学工艺和/或3D打印。此外，它将研究在多大程度上可以通过在多层中编写网络结构来生成微actor，其中执行器对不同的刺激作出反应。为此，多层体系由不同的材料生成，干燥后通过双光子过程在玻璃状状态下交联，从而使单个结构组件相互共价连接。通过这种方式，可以获得执行器，其中结构的部分可以逐渐受到外部刺激（例如光或湿度）的影响或打开/关闭。因此，微致动器可以产生，允许内在的传感和自主响应环境的变化。如果这些多响应致动器巧妙地组合在一起，应该可以实现一个多级致动器系统，其中每个阶段都是由外部刺激达到的。另一方面，在致动器场中，纤毛场的各个部分可以被外部刺激打开和关闭，从而可以研究新的合作现象。该项目还将研究如何使用新开发的方法生成双稳态和多稳态结构。对于双稳态结构，必须设计执行器，使系统可以通过简单的“弹跳”机制从一种稳定状态切换到另一种稳定状态，或者显示其他屈曲不稳定性。

Two-photon crosslinking (2PC) based on C,H insertion reactions allows the generation of microactuators from magnetic composites by a maskless direct writing process. To this copolymers are employed in which 2-photon chromophores such as suitably substituted anthraquinone groups are incorporated and which are cross-linked with the aid of 2-photon processes. This cross-linking process takes place in the glass-like state of the polymers. After completion of the writing process, all non-crosslinked polymer molecules are washed out to develop the microstructures. If nanoparticles have been mixed into the prepolymers before the deposition of the layer, three-dimensional microstructured nanocomposites can be obtained directly in a one-step process. Thus, with the help of such a maskless writing process, magnetically actuatable microstructures in almost any form can be written three-dimensionally which are self-supporting. In the proposed project, cooperative magnetically actuatable structures such as ciliated surfaces for micromixers or micropumps or actuator fields which show metachronal waves will be generated. By variation of the written structures, actuator fields with designed properties or actuators, which can act cooperatively can be generated. Larger structures can be generated by molding with the same polymers, but by a conventional photochemical process and/or 3D printing.Furthermore, it will be investigated to what extent microactors can be generated by writing network structures in multilayers in which the actuators react to different stimuli. For this purpose multilayered systems are generated from different materials and after drying they are cross-linked in a glass-like state by means of the two-photon process, so that the individual structural components are covalently linked to each other. In this way, actuators are obtained in which parts of the structures can be influenced either gradually or switched on/off by an external stimulus, for example light or moisture. Thus, microactuators can be generated that allow intrinsic sensing and an autonomous response to changes in the environment. If these multi-responsive actuators are skillfully combined, a multi-stage actuator system should be achievable in which the respective stage is reached by an external stimulus. On the other hand, looking at actuator fields the individual parts of the cilia fields could be switched on and off by the external stimulus, so that novel cooperative phenomena can be investigated.The proposed project will also investigate how bi- and multistable structures can be generated using the newly developed method. For bi-stable structures, actuators have to be designed where the system can be switched from one stable state to another by a simple "snap through" mechanism or showing other buckling instabilities.