Abstract: Flexible electronic technology has laid the foundation for complex human-computer interaction system, and has attracted great attention in the field of human motion detection and soft robotics. Graphene has received an extensive attention due to its excellent electrical conductivity; however, how to use it to fabricate wearable flexible sensors with complex structures remains challenging. In this study, we studied the rheological behavior of graphene/polydimethylsiloxane ink and proposed an optimal graphene ratio, which makes the ink have a good printability and conductivity at the same time. Then, based on the theory of Peano fractal layout, we proposed a two-dimensional structure that can withstand multi-directional tension by replacing the traditional arris structure with the arc structure. After that, we manufactured circular arc fractal structure sensor by adjusting ink composition and printing structure through direct ink writing method. Finally, we evaluated the detection performance and repeatability of the sensor. This method provides a simple and effective solution for fabricating wearable flexible sensors and exhibits the potential to fabricate 3D complex flexible electronic devices.

Key words: direct ink writing, conductive graphene ink, wearable flexible sensor, strain sensing, fractal structure

摘要： 柔性电子技术为复杂的人机交互系统奠定了基础，并在人体运动检测和软机器人领域引起了极大的关注。石墨烯由于其优异的导电性而受到广泛关注，然而，如何使用它来制造具有复杂结构的可穿戴柔性传感器仍然具有挑战性。在本研究中，我们研究了石墨烯/PDMS油墨的流变行为，并提出了最佳石墨烯比例，使油墨同时具有良好的印刷性和导电性。然后，基于Peano分形布局理论，我们提出了一种可以承受多向张力的二维结构，将传统的棱角结构替换为弧形结构。之后，我们通过直接墨水写入法调整墨水成分和打印结构，制造了圆弧分形结构传感器。最后，我们评估了传感器的检测性能和重复性。该方法为制造可穿戴柔性传感器提供了一种简单有效的解决方案，并显示出制造3D复杂柔性电子设备的潜力。

关键词: 直接墨水书写，导电石墨烯墨水，可穿戴柔性传感器，应变传感，分形结构