Department of Electronic Engineering , Kwangwoon University , 447-1 Wolgye-dong , Nowon-gu , Seoul 01897 , Republic of Korea.
ACS Appl Mater Interfaces. 2019 Jan 23;11(3):3438-3449. doi: 10.1021/acsami.8b17765. Epub 2019 Jan 8.
The rapid development of pressure sensors with distinct functionalities, notably, with increased sensitivity, fast response time, conformability, and a high degree of deformability, has increased the demand for wearable electronics. In particular, pressure sensors with an excellent sensitivity in the low-pressure range (<2 kPa) and a large working range simultaneously are strongly demanded for practical applications in wearable electronics. Here, we demonstrate an emerging class of solid polymer electrolyte obtained by incorporating a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with poly(vinylidene fluoride- co-hexafluoropropylene) as a high-capacitance dielectric layer for interfacial capacitive pressure sensing applications. The solid polymer electrolyte exhibits a very high interfacial capacitance by virtue of mobile ions that serve as an electrical double layer in response to an electric field. The randomly distributed microstructures created on the solid electrolyte help the material to elastically deform under pressure. Moreover, the interfacial capacitance is improved by utilizing a highly conductive porous percolated network of silver nanowires reinforced with poly(dimethylsiloxane) as the electrodes. An ultrahigh-pressure sensitivity of 131.5 kPa, a low dynamic response time of ∼43 ms, a low limit of detection of 1.12 Pa, and a high stability for over 7000 cycles are achieved. Finally, we demonstrate the application of the sensor for international Morse code detection, artery pulse detection, and eye blinking. Owing to the ultrahigh sensitivity, the as-fabricated sensor will have great potential for wearable devices in health status monitoring, motion detection, and electronic skin.
具有独特功能的压力传感器（尤其是灵敏度更高、响应时间更快、顺应性更好和可变形程度更高的压力传感器）得到了迅速发展，这增加了对可穿戴电子产品的需求。特别是，对于实际应用于可穿戴电子产品，同时具有优异的低压(<2 kPa)灵敏度和较大工作范围的压力传感器有强烈的需求。在这里，我们展示了一类新兴的固体聚合物电解质，它是通过将室温离子液体 1-乙基-3-甲基咪唑双（三氟甲烷磺酰）亚胺与聚（偏二氟乙烯-共-六氟丙烯）结合而成的，作为高电容介电层，用于界面电容压力传感应用。由于移动离子在电场作用下作为电双层，因此固体聚合物电解质具有非常高的界面电容。随机分布的微结构在固体电解质上的形成有助于材料在压力下弹性变形。此外，通过利用由聚二甲基硅氧烷增强的高度导电多孔渗流网络的银纳米线作为电极，提高了界面电容。该传感器实现了超高的压力灵敏度 131.5 kPa、低动态响应时间约 43 ms、低检测限 1.12 Pa 和超过 7000 次循环的高稳定性。最后，我们展示了该传感器在国际莫尔斯电码检测、动脉脉搏检测和眨眼检测方面的应用。由于超高的灵敏度，所制造的传感器将在健康状态监测、运动检测和电子皮肤等可穿戴设备中有很大的应用潜力。
