A versatile flexible piezoresistive sensor should maintain high sensitivity in a wide linear range, and provide a stable and repeatable pressure reading under bending. These properties are often difficult to achieve simultaneously with conventional filler–matrix composite active materials, as tuning of one material component often results in change of multiple sensor properties. Here, a material strategy is developed to realize a 3D graphene–poly(dimethylsiloxane) hollow structure, where the electrical conductivity and mechanical elasticity of the composite can be tuned separately by varying the graphene layer number and the poly(dimethylsiloxane) composition ratio, respectively. As a result, the sensor sensitivity and linear range can be easily improved through a decoupled tuning process, reaching a sensitivity of 15.9 kPa⁻¹ in a 60 kPa linear region, and the sensor also exhibits fast response (1.2 ms rising time) and high stability. Furthermore, by optimizing the density of the graphene percolation network and thickness of the composite, the stability and repeatability of the sensor output under bending are improved, achieving a measurement error below 6% under bending radius variations from −25 to +25 mm. Finally, the potential applications of these sensors in wearable medical devices and robotic vision are explored.

中文翻译：

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中空结构石墨烯-硅树脂复合压阻传感器：去耦特性调整和弯曲可靠性

通用的柔性压阻传感器应在宽线性范围内保持高灵敏度，并在弯曲下提供稳定且可重复的压力读数。这些特性通常很难与传统的填料-基质复合活性材料同时实现，因为一种材料成分的调整通常会导致多种传感器特性的改变。在这里，开发了一种材料策略来实现3D石墨烯-聚（二甲基硅氧烷）中空结构，其中复合材料的电导率和机械弹性可以分别通过改变石墨烯层数和聚（二甲基硅氧烷）组成比来分别调节。结果，通过解耦的调谐过程可以轻松提高传感器的灵敏度和线性范围，达到15.9 kPa的灵敏度在60 kPa线性区域中为^-1，并且该传感器还具有快速响应（上升时间1.2 ms）和高稳定性。此外，通过优化石墨烯渗滤网络的密度和复合材料的厚度，弯曲时传感器输出的稳定性和可重复性得到了改善，在从-25到+25 mm的弯曲半径变化下，实现了低于6％的测量误差。最后，探讨了这些传感器在可穿戴医疗设备和机器人视觉中的潜在应用。