Many capacitive or resistive humidity sensors cannot accurately measure high humidity because of surface water condensation and saturation of hygrosopic material in the sensors. Here, we propose a novel method of high humidity measurement using a ‘hydromorphic’ dielectric elastomer actuator (DEA). This novel humidity sensor consists of a ‘relatively water-inert’ acrylic dielectric elastomer layer (3M VHB 4910) sandwiched by a pair of hygroscopic polymer electrodes. The hygroscopic polymer electrodes are made of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS); they become softer upon moisture absorption while enabling moisture permeation into the dielectric elastomer substrate during electrical activation and read-out. While the dielectric elastomeric actuation (under constant voltage) enlarged with increasing humidity, the current leaked through it rose more significantly. This suggests a strong humidity dependence of dielectric resistivity. Experimental correlation showed the dielectric resistance be a piecewise linear function of humidity. Further, this DEA-based humidity sensor remained working when both its electrodes were sprayed with a mist of water droplets.

由于表面水的凝结和传感器中吸湿物质的饱和，许多电容式或电阻式湿度传感器无法准确测量高湿度。在这里，我们提出了一种使用“氢态”介电弹性体致动器（DEA）进行高湿度测量的新方法。这种新颖的湿度传感器由“相对水惰性”的丙烯酸介电弹性体层（3M VHB 4910）夹在一对吸湿聚合物电极之间。吸湿性聚合物电极由聚（3,4-乙撑二氧噻吩）聚苯乙烯磺酸盐（PEDOT：PSS）制成；它们在吸收水分后变软，同时在电激活和读出过程中使水分渗透到介电弹性体基材中。当介电弹性体驱动（在恒定电压下）随着湿度的增加而扩大时，通过它泄漏的电流上升得更大。这表明介电电阻率对湿度的依赖性强。实验相关性表明，介电电阻是湿度的分段线性函数。此外，当这两个基于DEA的湿度传感器的两个电极都喷有水滴时，它仍然可以工作。