Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstr. 69, 14476 Potsdam, Germany.
Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstr. 11, 79108 Freiburg, Germany.
Molecules. 2021 Jan 20;26(3):522. doi: 10.3390/molecules26030522.
For soft robotics and programmable metamaterials, novel approaches are required enabling the design of highly integrated thermoresponsive actuating systems. In the concept presented here, the necessary functional component was obtained by polymer syntheses. First, poly(1,10-decylene adipate) diol (PDA) with a number average molecular weight of 3290 g·mol was synthesized from 1,10-decanediol and adipic acid. Afterward, the PDA was brought to reaction with 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. The resulting polyester urethane (PEU) was processed to the filament, and samples were additively manufactured by fused-filament fabrication. After thermomechanical treatment, the PEU reliably actuated under stress-free conditions by expanding on cooling and shrinking on heating with a maximum thermoreversible strain of 16.1%. Actuation stabilized at 12.2%, as verified in a measurement comprising 100 heating-cooling cycles. By adding an actuator element to a gripper system, a hen's egg could be picked up, safely transported and deposited. Finally, one actuator element each was built into two types of unit cells for programmable materials, thus enabling the design of temperature-dependent behavior. The approaches are expected to open up new opportunities, e.g., in the fields of soft robotics and shape morphing.
对于软机器人技术和可编程超材料，需要新的方法来设计高度集成的热响应致动系统。在本文提出的概念中，通过聚合物合成获得了必要的功能组件。首先，由 1,10-癸二醇和己二酸合成了数均分子量为 3290 g·mol 的聚（癸二酸 1,10-癸二醇酯）（PDA）。然后，将 PDA 与 4,4'-二苯甲烷二异氰酸酯和 1,4-丁二醇进行反应。得到的聚酯型聚氨酯（PEU）被加工成纤维，通过熔融纺丝制造样品。经过热机械处理，PEU 在无应力条件下可靠地进行致动，在冷却时膨胀，在加热时收缩，最大热可逆应变可达 16.1%。通过 100 次加热-冷却循环的测量验证，致动稳定在 12.2%。通过在夹具系统中添加致动器元件，可以捡起、安全运输和放置鸡蛋。最后，在两种类型的单元胞中各构建一个致动器元件，从而能够设计出温度依赖性的行为。这些方法有望开辟新的机会，例如在软机器人技术和形状变形领域。
