van Hazendonk Laura S, Khalil Zafeiris J, van Grondelle Wilko, Wijkhuijs Levina E A, Schreur-Piet Ingeborg, Debije Michael G, Friedrich Heiner
Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands.
Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. box 513, Eindhoven 5600 MB, The Netherlands.
ACS Appl Mater Interfaces. 2024 Jun 26;16(25):32739-32747. doi: 10.1021/acsami.4c06130. Epub 2024 Jun 13.
Liquid crystal-based actuators are receiving increased attention for their applications in wearables and biomedical or surgical devices, with selective actuation of individual parts/fingers still being in its infancy. This work presents the design and realization of two gripper devices with four individually addressable liquid-crystal network (LCN) actuators thermally driven via printed graphene-based heating elements. The resistive heat causes the all-organic actuator to bend due to anisotropic volume expansions of the splay-aligned sample. A heat transfer model that includes all relevant interfaces is presented and verified via thermal imaging, which provides good estimates of dimensions, power production, and resistance required to reach the desired temperature for actuation while maintaining safe electrical potentials. The LCN films displace up to 11 mm with a bending force of 1.10 mN upon application of 0-15 V potentials. The robustness of the LCN finger is confirmed by repetitive on/off switching for 500 cycles. Actuators are assembled into two prototypes able to grip and lift objects of small weights (70-100 mg) and perform complex actions by individually controlling one of the device's fingers to grip an additional object. Selective actuation of parts in soft robotic devices will enable more complex motions and actions to be performed.
基于液晶的致动器因其在可穿戴设备以及生物医学或手术器械中的应用而受到越来越多的关注，而单个部件/手指的选择性致动仍处于起步阶段。这项工作展示了两种夹持器装置的设计与实现，它们具有四个可单独寻址的液晶网络（LCN）致动器，通过基于印刷石墨烯的加热元件进行热驱动。电阻热会使全有机致动器因展向排列样品的各向异性体积膨胀而弯曲。提出了一个包含所有相关界面的传热模型，并通过热成像进行了验证，该模型能很好地估算尺寸、发电量以及在保持安全电势的同时达到所需致动温度所需的电阻。施加0 - 15 V电势时，LCN薄膜在1.10 mN的弯曲力作用下位移可达11 mm。通过500次重复的开/关切换，证实了LCN手指的稳健性。致动器被组装成两个原型，能够抓取和提起小重量（70 - 100 mg）的物体，并通过单独控制设备的一个手指来抓取另一个物体，从而执行复杂动作。软机器人设备中部件的选择性致动将能够执行更复杂的运动和动作。
